Dental composition and use thereof

ABSTRACT

The invention relates to a dental composition comprising polymerizable monomer (1), initiator component(s), filler component(s) in an amount of more than about 20 wt.-%, wt.-% with respect to the whole weight of the composition, the polymerizable monomer (1) being characterized as follows: having exactly two (meth)acrylate reactive moieties, having an unsymmetrical backbone as linkage between the (meth)acrylate reactive moieties, the two (meth)acrylate reactive moieties being attached onto the unsymmetrical monomer backbone as alkyl esters, the unsymmetrical backbone comprising one aromatic moiety of the phenolic type, the polymerizable monomer (1) not containing an acidic moiety, other atoms than carbon, hydrogen, and oxygen, bisphenol moieties. The invention also relates to the use of the dental composition as or for producing a dental filling material, crown and bridge material, inlay, onlay, veneer or dental mill blank.

FIELD OF THE INVENTION

The invention relates to a dental composition which is in particularuseful for restorative purposes. The composition comprises a hardenableresin matrix comprising non-acidic hardenable components, a filler andan initiator and shows improved physical properties like compressivestrength.

BACKGROUND ART

There are different dental filling materials which are used forrestorative purposes, including amalgam and dental composite materials.

In order to fulfill its function (replacement of lost tooth structure),dental filling materials need to have adequate physical properties. Inparticular, they have to have sufficient strength to be able to absorband resist chewing forces.

If, however, the material is too hard, it will also become more brittle.

Thus, a dental filling material not only needs to be sufficiently hard,but also needs to be to some extend flexible.

To address these needs, commercially available dental composite fillingmaterials typically contain a certain amounts of resin matrix, fillerand initiator.

A widely used polymerizable (meth)acrylate component contained in theresin matrix is bisphenol A-glycidyl methacrylate (Bis-GMA) or otherbisphenol based (meth)acrylate monomers.

Compositions containing bisphenol-based monomers are said to have avariety of advantageous properties like high compressive strength, thusenabling the practitioner to formulate a variety of different dentalcompositions for restorative purposes.

Some literature, however, seems to indicate that bisphenol basedmonomers are not always recommended for all purposes. Alternativepolymerizable (meth)acrylate components are thus needed.

US 2010/076115 (Heraeus Kulzer) relates to compositions for dentalcomposites comprising acrylic acid esters of tricyclo[5.2.1.02.6] decanewith urethane groups

U.S. Pat. No. 3,853,962 (Gander) relates to dental restorative cementscomprising the methacrylate monomer 1,3-bis[2-,3-di(methacryloxy)-propoxy]-benzene. Restorative compositionscontaining this kind of monomer are said to have improved compressivestrength and related physical properties.

U.S. Pat. No. 4,744,827 (Winkel) describes (meth)acrylic acidderivatives of a tricyclodecane exhibiting considerably lesspolymerization shrinkage.

WO 2012/003136 (3M) relates to a dental composition comprising ahardenable compound with a comparable rigid backbone, which may compriseurethane moieties. The composition is said to have advantageousproperties e.g. with respect to shrinkage stress.

WO 2009/042574 (3M) describers methacrylate based monomers containing aurethane linkage showing a well balanced properties with respect toviscosity, refractive index, molecular weight and shrinkage value.

U.S. Pat. No. 4,539,382 (Omura et al) describes a method of restoring acarious tooth, the method comprising applying to the wall surface of acavity in a carious tooth an adhesive composition comprising a certainamount of a certain polymerizable monomer, a certain amount of acopolymerizable vinyl monomer and a certain amount of a curing agent,and filling said cavity with a dental filling composition.

US 2011/0315928 A1 (Jin at al.) relates to a low viscosity and lowstress dental composition comprising at least one low stresspolymerizable resin and at least one filler. The dental composition aresaid to have high depth of cure and self-leveling characteristics andare capable of bulk application.

WO 2012/106083 A1 (3M) relates to a dental composition comprising acertain compound (A), a filler (B), and an initiator (C), whereincompound (A) comprises a certain backbone unit and one or two spacerunits having a certain structure.

JP 61-012709 (Mitsui) relates to a composition containingpoly(methacryloxypolyethoxy)benzene, vinyl compounds and a curingcatalyst, giving cured products of high water resistance and beingsuitable for dental purposes.

J. M. Antonucci et al. describes in J. Dent. Res. 1976, 55:8 thesynthesis of dimethacrylates derived from hydroxybenzoic acids. Theobtained monomers are said to be crystalline and are suggested forpossible evaluation in composites and pit and fissure sealantformulations, however, without describing any working example.

DESCRIPTION OF THE INVENTION

Generally, there is a need for a dental composition having adequatephysical properties, which can be formulated without the need of usingBis-GMA or other bisphenol based (meth)acrylate monomers or components.

In particular, it is one object of the present invention to provide adental composition showing improved physical properties, likecompressive strength, wherein the dental composition ideally does notcomprise bisphenol moieties containing (meth)acrylate components.

To address this object, the present invention features a dentalcomposition as described in the claims comprising

-   -   Polymerizable monomer (1),    -   Initiator component(s),    -   Filler component(s) in an amount of more than about 20 wt.-%,        wt.-% with respect to the whole weight of the composition,        the polymerizable monomer (1) being characterized as follows:    -   having exactly two (meth)acrylate reactive moieties,    -   having an unsymmetrical backbone as linkage between the        (meth)acrylate reactive moieties,    -   the two (meth)acrylate reactive moieties being attached onto the        unsymmetrical monomer backbone as alkyl esters,    -   the unsymmetrical backbone comprising typically exactly one        aromatic moiety of the phenolic type,        the polymerizable monomer (1) not containing    -   other atoms than carbon, hydrogen, and oxygen,    -   other aromatic moieties than aromatic moieties of the phenolic        type,    -   bisphenol moieties.

Moreover, the invention features a method of using the composition asdescribed in the text of the invention for producing or as dentalfilling material, crown and bridge material (e.g. temporary andlong-term), inlay, onlay, veneer, orthodontic device or dental millblank.

The invention is also related to the use of the dental composition asdescribed in the present text for producing a dental restoration like adental crown, bridge, onlay or inlay by applying a rapid-prototypingtechnique.

Unless defined differently, for this description the following termsshall have the given meaning:

A “dental composition” or a “composition for dental use” or a“composition to be used in the dental field” is any composition whichcan and is to be used in the dental field. In this respect thecomposition should not be detrimental to the patients' health and thusfree of hazardous and toxic components being able to migrate out of thecomposition. Examples of dental compositions include permanent andtemporary crown and bridge materials, artificial crowns, anterior orposterior filling materials, dental mill blanks and orthodontic devices.

Dental compositions are typically hardenable compositions. Dentalcompositions for hardening in the mouth can be hardened at ambientconditions, including a temperature range from about 15 to 50° C. orfrom about 20 to 40° C. within a time frame of about 30 min or 20 min or10 min. Higher temperatures are not recommended as they might cause painto the patient and may be detrimental to the patient's health. Dentalcompositions are typically provided to the practitioner in comparablesmall volumes, that is volumes in the range from about 0.1 to about 100ml or from about 0.5 to about 50 ml or from about 1 to about 30 ml.Thus, the storage volume of useful packaging devices is typically withinthese ranges.

A “dental filling material” is a hardenable material designed to restoremissing tooth structure, in particular to fill a cavity in hard dentaltissue.

A “crown and bridge material” within the meaning of the invention is ahardenable material used for making dental crowns and bridges. Thesematerials are typically used during the time period a dental technicianneeds for producing a permanent prosthetic work such as a crown orbridge. These time periods can last from a few days (1 to about 6 days),a few weeks (1 to about 4 weeks) or a few months (1 to about 6 month). Along term crown and bridge material is typically used over a time periodof about 6 to 24 months.

By “dental milling block” or “dental mill blank” is meant a solid block(3-dim article) of material from which a dental article can be machined.A dental milling block has typically a geometrically defined shape. Adental milling block may have a size of about 20 mm to about 30 mm intwo dimensions, for example may have a diameter in that range, and maybe of a certain length in a third dimension. A block or blank for makinga single crown may have a length of about 15 mm to about 30 mm, and ablock or blank for making bridges may have a length of about 40 mm toabout 80 mm. A typical size of a block or blank as it is used for makinga single crown has a diameter of about 24 mm and a length of about 19mm. Further, a typical size of a block or blank as it is used for makingbridges has a diameter of about 24 mm and a length of about 58 mm.Besides the above mentioned dimensions, a dental milling block may alsohave the shape of a cube, a cylinder or a cuboid. Larger milling blocksmay be advantageous if more than one crown or bridge should bemanufactured out of one blank. For these cases, the diameter or lengthof a cylindric or cuboid shaped mill blank may be in a range of about 80to about 200 mm, with a thickness being in the range of about 10 toabout 30 mm.

By “machining” is meant milling, grinding, cutting, carving, or shapinga material by a machine. Milling is usually faster and more costeffective than grinding.

An “initiator system” or “initiator” shall include those components ofthe dental composition being able to start or initiate the curingprocess of the hardenable components, also described herein as “curingthe hardenable components”.

A “resin matrix” shall mean the organic part of the dental compositionbeing composed of the hardenable components and organic diluents, ifpresent.

A “hardenable component or material” (e.g., “polymerizable component” or“crosslinkable component”) is any component which can be cured orsolidified e.g., by heating to cause polymerization, chemicalcrosslinking, radiation-induced polymerization or crosslinking by usinga redox initiator. A hardenable component may contain, for example, onlyone, two, three or more polymerizable groups. Typical examples ofpolymerizable groups include unsaturated carbon groups, such as a vinylgroup being present e.g. in a (meth)acrylate group.

A “curable composition” is a mixture of two or more components, themixture being able to be cured or solidified e.g., by heating to causechemical crosslinking, radiation-induced polymerization or crosslinkingby using a redox initiator. A curable composition may advantageouslyinclude a hardenable component.

A “monomer” is any chemical substance which can be characterized by achemical formula, bearing one or more polymerizable groups (including(meth)acrylate groups) which can be polymerized to oligomers or polymersthereby increasing the molecular weight. The molecular weight ofmonomers can usually simply be calculated based on the chemical formulagiven.

As used herein, “(meth)acryl” is a shorthand term referring to “acryl”and/or “methacryl”. For example, a “(meth) acryloxy” group is ashorthand term referring to either an acryloxy group (i. e.,CH₂═CH—C(O)—O—) and/or a methacryloxy group (i. e., CH₂═C(CH₃)—C(O)—O—).Similarly, (meth)acrylate is a shorthand term referring to “acrylate”and/or “methacrylate.”

“Curing,” “hardening,” and “setting reaction” are used interchangeablyand refer to a reaction wherein physical properties such as viscosityand hardness of a composition change (e.g., increase) over time due to achemical reaction between the individual components.

A “polymerizable monomer(s) with acidic moieties” is meant to includemonomers, oligomers, and polymers having ethylenic unsaturation and acidand/or acid-precursor functionality. Acidic-precursor functionalitiesinclude, e.g. anhydrides, acid halides and pyrophosphates. The acidicgroup preferably comprises one or more carboxylic acid residues, such as—COOH or —CO—O—CO—, phosphoric acid residues, such as —O—P(O)(OH)OH,phosphonic acid residues such as C—P(O)(OH)OH, sulfonic acid residues,such as —SO₃H or sulfinic acid residues such as —SO₂H.

A “phenolic type” moiety is generally understood as an aromatic moietybearing at least one oxygen atom directly attached onto an aromaticresidue, more precisely, a moiety comprising the structural element[C6RxO] with x being 1, 2, 3, 4, 5 or 6, R being H, alkyl (e.g. C1 toC8), —O—, —CO— or —C(O)O— and C6 forming an aromatic ring. For example,“C6HSO—” (phenoxy) represents the most simple “phenolic type” moiety.

A “powder” means a dry, bulk solid composed of a large number of veryfine particles that may, for example, flow freely when shaken or tilted.

A “particle” means a substance being a solid having a shape which can begeometrically determined. Particles can typically be analysed withrespect to e.g. particle size or diameter. Particles may be amorphous orcrystalline.

“Radiation curable” shall mean that the component (or composition, asthe case may be) can be cured by applying radiation, preferablyelectromagnetic radiation with a wavelength in the visible lightspectrum under ambient conditions and within a reasonable time frame(e.g. within about 15, 10 or 5 min).

The term “visible light” is used to refer to light having a wavelengthof about 400 to about 700 nanometers (nm).

“Hard dental tissue” means dentin and enamel.

“Ambient conditions” mean the conditions which the inventive compositionis usually subjected to during storage and handling. Ambient conditionsmay, for example, be a pressure of about 900 to about 1100 mbar, atemperature of about −10 to about 60° C. and a relative humidity ofabout 10 to about 100%. In the laboratory ambient conditions can beadjusted to about 23° C. and about 1013 mbar and about 50% relativehumidity. In the dental and orthodontic field ambient conditions arereasonably understood as a pressure of about 950 to about 1050 mbar,temperature of about 15 to about 40° C. and relative humidity of about20 to about 80%.

A composition is “essentially or substantially free of” a certaincomponent within the meaning of the invention, if the composition doesnot contain said component as an essential feature. Thus, said componentis not willfully added to the composition either as such or incombination with other components or ingredient of other components. Acomposition being essentially free of a certain component usuallycontains the component in an amount of less than about 1 wt.-% or lessthan about 0.1 wt.-% or less than about 0.01 wt.-% with respect to thewhole composition. Ideally, the composition or solution does not containthe said component at all. However, sometimes the presence of a smallamount of the said component is not avoidable e.g. due to impurities.

As used herein, “a”, “an”, “the”, “at least one” and “one or more” areused interchangeably. The terms “comprises” or “contains” and variationsthereof do not have a limiting meaning where these terms appear in thedescription and claims. The term “comprising” also includes the morelimited expressions “consisting essentially of” and “consisting of”.

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, 5, etc.).

Adding an “(s)” to a term means that the term should include thesingular and plural form. E.g. the term “additive(s)” means one additiveand more additives (e.g. 2, 3, 4, etc.).

Unless otherwise indicated, all numbers expressing quantities ofingredients, measurement of physical properties such as described belowand so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.”

DETAILED DESCRIPTION OF THE INVENTION

It has been found that the composition described in the present text issuperior with respect to a variety of properties:

A hardened dental composition comprising the asymmetric (i.e. nonsymmetric), polymerizable monomers described in the present text showsimproved physical properties, especially with respect to compressivestrength.

Further, the desired dental composition can be formulated without usingbisphenol moiety(s) containing monomers or components.

The asymmetric, polymerizable monomers described in the present texttypically do not solidify at room temperature and thus facilitate theincorporation of a sufficient amount of filler, an amount which istypically needed for formulating or producing a dental filling or crownand bridge material or dental mill blank.

In certain embodiments the dental composition fulfills at least one ormore, sometimes all of the following features before hardening:

-   -   Viscosity: being a paste, e.g. having a viscosity from about 0.5        to about 200 Pa*s or from about 1 to about 100 Pa*s measured at        23° C. with a shear rate of 100 l/s;    -   pH value, if brought in contact with water: neutral (e.g. about        6 to about 8) or acidic (e.g. about 2 to about 5);    -   radiation or redox curable;    -   storage stable;    -   being provided as a one or two-component system.

If desired and more precisely, the viscosity can be determined under thefollowing conditions: 23° C.; shear rate: 100 l/s; measured with acone/plate geometry CP25-1 with a Physica MCR 301 Rheometer, Anton PaarGmbH, Graz, Austria.

If dissolved or dispersed in water (e.g. 1 g composition in 10 ml water)the composition typically exhibits a pH value in the range from about 6to about 8 or about 7. That is, the composition as a whole essentiallyhas a neutral pH, if brought in contact with water, or is slightlyacidic.

The invention provides a composition which can be hardened in anacceptable time frame, e.g., less than about 300 seconds (s) or lessthan about 180 s or less than about 120 s, and to a sufficient depthusing visible light source equipment already available in the dentaloffice.

In certain embodiments the dental composition fulfills at least one ormore, sometimes all of the following properties (after hardening):

-   -   compressive strength (CS1) of the dental formulation determined        according to ISO 4049 using specimens having the dimension of 3        mm×3 mm×5 mm: at least about 430 MPa or at least about 445 or at        least about 460 MPa,    -   compressive strength (CS2) of the dental formulation determined        according to DIN 53454 (ISO 9917 2001) using cylindrical        specimens with a diameter of 4 mm and a height of 8 mm: at least        about 280 MPa or at least about 300 or at least about 320 MPa.

The polymerizable monomer (1) is one component of the hardenable resinmatrix contained in the dental adhesive composition.

The polymerizable monomer (1) can be described as follows:

-   -   having exactly two (meth)acrylate reactive moieties,    -   having an unsymmetrical backbone as linkage between the        (meth)acrylate reactive moieties,    -   the two (meth)acrylate reactive moieties being attached onto the        unsymmetrical monomer backbone as alkyl esters,    -   the unsymmetrical backbone comprising exactly one aromatic        moiety of the phenolic type,    -   preferably containing not more than one additional aromatic        moiety within the unsymmetrical monomer backbone not being part        of the linkage between the reactive groups but being attached        onto this linkage between the reactive groups,    -   preferably having exactly two (meth)acrylate reactive groups        that are always attached onto the unsymmetrical monomer backbone        as alkyl esters,        the polymerizable monomer (1) not containing    -   other atoms than carbon, hydrogen, and oxygen,    -   other aromatic moieties than aromatic moieties of the phenolic        type,    -   bisphenol moieties,    -   optionally other oxygen based linkages than ethers and esters.

According to one embodiment, the polymerizable monomer (1) can also becharacterized by the following features:

-   -   having a molecular weight of about 300 to about 600,    -   not solidifying at room temperature (e.g. 23° C.), that is being        a liquid.        Polymerizable monomer (1) is characterized by the following        formula (I):

with:

-   B—O-A[-O—-B′—]_(a) representing the unsymmetrical monomer backbone    as linkage between the reactive groups,-   a=0 or 1,    A being selected from the following moieties:

-   A being always attached as aryl-alkyl ether onto B and/or B′,    B being selected from the following moieties:-   *—(CH₂)_(b)—*, *—(CH₂—CH₂—O—CH₂—CH₂)—*, *—(CH₂—CH₂—O—CH₂—CH₂—CH2—*,    *—(CH₂—CH₂—CH₂—O—CH₂—CH₂—CH₂)—,

-   B being always attached as alkyl ester onto the (meth)acrylate    reactive moiety,-   b=2 to 6,-   B′ being selected from *—(CH2)_(b′)—*, *—(CH₂—CH₂—O—CH₂—CH₂)—*,

-   B′ being always attached as alkyl ester onto the (meth)acrylate    reactive moiety,-   b′=2 to 6,-   R═H, methyl,-   X being selected from H, methyl, ethyl, hexyl, tert-butyl,-   “*” representing those sites of a moiety of the monomer, where that    moiety is bonded to another moiety of the monomer.    According to a further embodiment the polymerizable monomer (1) can    be characterized by either of formula (Ia) or formula (Ib):

with:

-   B—O-A-O—B′ being an unsymmetrical monomer backbone as linkage    between the reactive moieties,    A being selected from the moieties:

-   A being always attached as aryl-alkyl ether onto B and B′,    B being selected from the moieties:-   *—(CH₂)_(b)—*, *—(CH₂—CH₂—O—CH₂—CH₂)—*, *—(CH₂—CH₂—O—CH₂—CH₂—CH₂)—*,    *—(CH₂—CH₂—CH₂—O—CH₂—CH₂—CH₂)—*,

-   B being always attached as alkyl ester onto the (meth)acrylate    reactive moiety,-   b=2 to 6,    B′ being selected from the moieties:-   *—(CH₂)_(b)—*, *—(CH₂—CH₂—O—CH₂—CH₂)—*, *—(CH₂—CH₂—O—CH₂—CH₂—CH₂)—*,    *—(CH₂—CH₂—CH₂—O—CH₂—CH₂—CH₂)—*

-   B′ being always attached as alkyl ester onto the (meth)acrylate    reactive moiety,-   b′=2 to 6,-   R═H, methyl,-   X═H, methyl, ethyl, hexyl, tert-butyl;    or

with:

-   B—O-A being an unsymmetrical monomer backbone as linkage between the    reactive moieties,    A being selected from the moieties:

-   A being always attached as aryl-alkyl ether onto B and always    attached as alkyl ester onto the (meth)acrylate reactive moiety,    B being selected from:-   —(CH₂)_(b)—* , *—(CH₂—CH₂—O—CH₂—CH₂)—*,

-   B being always attached as alkyl ester onto the (meth)acrylate    reactive moiety,-   b=2 to 6,-   R═H, methyl;-   “*” representing those sites of a moiety of the monomer, where that    moiety is bonded to another moiety of the monomer.    Specific examples of for the polymerizable monomer (1) include:

In all the above formulas R can independently be selected from H andCH3, meaning that in each component R can be either methyl or hydrogen,or that one R is methyl and the other R is hydrogen.

The polymerizable monomers (1) described in the present text can besynthesized e.g. as described in the example section below.

When doing so, the skilled person will realize that depending on thepolymerizable monomer (1) during synthesis a single non-symmetricalcompound is obtained as well as a mixture containing differentnon-symmetrical components or a mixture containing minor symmetricalcomponents besides the major non-symmetrical compound is obtained.

For a polymerizable monomer (1) containing a non-symmetrical backbonebased on a non-symmetrically substituted aromatic moiety, the synthesiswill result either in a single non-symmetrical compound or in acomposition containing 100 mol-% of non-symmetrical components.

Unless further purified, the synthesis of a polymerizable monomer (1)containing a non-symmetrical backbone which is based on a symmetricallysubstituted aromatic moiety, will usually result—due to statistics—in acomposition containing about 50 mol-% of the non-symmetrical compound asthe major component besides about 25 mol-% each of symmetrical compoundsas minor components.

Mixtures of two, three or more of the polymerizable monomers (1) can beused, if desired.

The polymerizable monomer (1) is typically contained in the followingamounts:

-   -   Lower limit: at least about 1 or at least about 5 or at least        about 10 wt.-%    -   Upper Limit: up to about 75 or up to about 70 or up to about 65        wt.-%    -   Range: from about 1 to about 75 or from about 5 to about 70 or        from about 10 to about 65 wt.-%,        wt.-% with respect to the amount of the whole composition.

Besides polymerizable monomer(s) without acidic groups, the compositioncan also comprise polymerizable monomer(s) with acidic moieties (2) aspart of the resin matrix.

Thus, the composition described in the present text may further comprisea polymerizable monomer (2) with an acidic moiety.

If present, the nature and structure of polymerizable monomer (2) is notparticularly limited, either unless the desired result cannot beachieved.

The presence of polymerizable monomer (3) can be beneficial because itcan provide the composition with a desired acidity.

The polymerizable components with acid moiety (Al) can typically berepresented by the following formula

A_(n)-B—C_(m)

with A being an ethylenically unsaturated group, such as a (meth)acrylmoiety,

-   B being a spacer group, such as (i) linear or branched C1 to C12    alkyl, optionally substituted with other functional groups (e.g.    halogenides (including Cl, Br, I), OH or mixtures thereof) (ii) C6    to C12 aryl, optionally substituted with other functional groups    (e.g. halogenides, OH or mixtures thereof), (iii) organic group    having 4 to 20 carbon atoms bonded to one another by one or more    ether, thioether, ester, thioester, thiocarbonyl, amide, urethane,    carbonyl and/or sulfonyl linkages,and-   C being an acidic group,-   m, n being independently selected from 1, 2, 3, 4, 5 or 6,    wherein the acidic group comprises one or more carboxylic acid    residues, such as —COOH or —CO—O—CO—, phosphoric acid residues, such    as —O—P(O)(OH)OH, phosphonic acid residues, such as C—P(O)(OH)(OH),    sulphonic acid residues, such as —SO₃H or sulfinic acid residues    such as —SO₂H.

Examples of polymerizable components with acid moiety include, but arenot limited to glycerol phosphate mono(meth)acrylate, glycerol phosphatedi(meth)acrylate, hydroxyethyl (meth)acrylate (e.g., HEMA) phosphate,bis((meth)acryloxyethyl) phosphate, (meth)acryloxypropyl phosphate,bis((meth)acryloxypropyl) phosphate, bis((meth)acryloxy)propyloxyphosphate, (meth)acryloxyhexyl phosphate, bis((meth)acryloxyhexyl)phosphate, (meth)acryloxyoctyl phosphate, bis((meth)acryloxyoctyl)phosphate, (meth)acryloxydecyl phosphate, bis((meth)acryloxydecyl)phosphate, caprolactone methacrylate phosphate, citric acid di- ortri-methacrylate, poly(meth)acrylated oligomaleic acid,poly(meth)acrylated polymaleic acid, poly(meth)acrylatedpoly(meth)acrylic acid, poly(meth)acrylated polycarboxyl-polyphosphonicacid, poly(meth)acrylated polychlorophosphoric acid, poly(meth)acrylatedpolysulfonate, poly(meth)acrylated polyboric acid, and the like.Derivatives of these hardenable components bearing an acid moiety thatcan readily react e.g. with water to form the specific examplesmentioned above, like acid halides or anhydrides are also contemplated.

Also monomers, oligomers, and polymers of unsaturated carboxylic acidssuch as (meth)acrylic acids, aromatic (meth)acrylated acids (e.g.,methacrylated trimellitic acids), and anhydrides thereof can be used.

Some of these compounds can be obtained, e.g., as reaction productsbetween isocyanatoalkyl (meth)acrylates and carboxylic acids. Additionalcompounds of this type having both acid-functional and ethylenicallyunsaturated components are described in U.S. Pat. No. 4,872,936(Engelbrecht) and U.S. Pat. No. 5,130,347 (Mitra). A wide variety ofsuch compounds containing both the ethylenically unsaturated and acidmoieties can be used. If desired, mixtures of such compounds can beused.

Using (meth)acrylate functionalized polyalkenoic acids is oftenpreferred as those components were found to be useful to improveproperties like adhesion to hard dental tissue, formation of ahomogeneous layer, viscosity, or moisture tolerance.

According to one embodiment, the composition contains (meth)acrylatefunctionalized polyalkenoic acids, for example, AA:ITA:IEM (copolymer ofacrylic acid:itaconic acid with pendent methacrylates).

These components can be made by reacting e.g. an AA:ITA copolymer with2-isocyanatoethyl methacrylate to convert at least a portion of the acidgroups of the copolymer to pendent methacrylate groups. Processes forthe production of these components are described, e.g., in Example 11 ofU.S. Pat. No. 5,130,347 (Mitra)); and those recited in U.S. Pat. No.4,259,075 (Yamauchi et al.), U.S. Pat. No. 4,499,251 (Omura et al.),U.S. Pat. No. 4,537,940 (Omura et al.), U.S. Pat. No. 4,539,382 (Omuraet al.), U.S. Pat. No. 5,530,038 (Yamamoto et al.), U.S. Pat. No.6,458,868 (Okada et al.), and EP 0 712 622 A1 (Tokuyama Corp.) and EP 1051 961 A1 (Kuraray Co., Ltd.).

Mixtures of two, three or more of the polymerizable monomers (2) can beused, if desired.

The polymerizable monomer with acidic moieties (2) can be present in thefollowing amounts:

-   -   Lower limit: at least about 0 or at least about 0.1 or at least        about 1 wt.-%,    -   Upper Limit: up to about 60 or up to about 50 or up to about 40        wt.-%,    -   Range: from about 0 to about 60 or from about 0.1 to about 50 or        from about 1 to about 40 wt.-%,        wt.-% with respect to the amount of the whole composition.

The composition described in the present text may optionally alsocomprise a polymerizable monomer (3) without an acidic moiety beingdifferent from the polymerizable monomer (1), in particular apolymerizable monomer comprising a urethane moiety.

If present, the polymerizable monomer (3) forms a further component ofthe hardenable resin matrix.

The nature and structure of polymerizable monomer (3) is notparticularly limited, either unless the desired result cannot beachieved.

This component is typically a free-radically polymerizable material,including ethylenically unsaturated monomer, monomers or oligomers orpolymers.

Suitable polymerizable components can be characterized by the followingformula:

A_(n)-B-A_(m)

with A being an ethylenically unsaturated group, such as a (meth)acrylmoiety,

-   B being selected from (i) linear or branched C1 to C12 alkyl,    optionally substituted with other functional groups (e.g.    halogenides (including Cl, Br, I), OH or mixtures thereof) (ii) C6    to C12 aryl, optionally substituted with other functional groups    (e.g. halogenides, OH or mixtures thereof), or (iii) organic group    having 4 to 20 carbon atoms bonded to one another by one or more    ether, thioether, ester, thioester, thiocarbonyl, amide, urethane,    carbonyl and/or sulfonyl linkages,-   m, n being independently selected from 0, 1, 2, 3, 4, 5 or 6 with    the proviso that n+m is greater 0, that is that at least one A group    is present.

Such polymerizable materials include mono-, di- or poly-acrylates andmethacrylates such as methyl acrylate, methyl methacrylate, ethyl(meth)acrylate, isopropyl (meth)acrylate, n-hexyl (meth)acrylate,stearyl (meth)acrylate, allyl (meth)acrylate, glycerol di(meth)acrylate,the diurethane dimethacrylate called UDMA (mixture of isomers, e.g. RohmPlex 6661-0) being the reaction product of 2-hydroxyethyl methacrylate(HEMA) and 2,2,4-trimethylhexamethylene diisocyanate (TMDI), glyceroltri(meth)acrylate, ethyleneglycol di(meth)acrylate, diethyleneglycoldi(meth)acrylate, triethyleneglycol di(meth)acrylate, 1,3-propanedioldiacrylate, 1,3-propanediol dimethacrylate, 1,6 hexandioldi(meth)acrylate, 1,10 decanediol di(meth)acrylate, 1,12 dodecanedioldi(meth)acrylate, trimethylolpropane tri(meth)acrylate,1,2,4-butanetriol tri(meth)acrylate, 1,4-cyclohexanedioldi(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritoltetraacrylate, pentaerythritol tetramethacrylate, sorbitolhexa(meth)acrylate,bis[1-(2-(meth)acryloxy)]-p-ethoxyphenyldimethylmethane, andtrishydroxyethyl-isocyanurate trimethacrylate; the bis-acrylates andbis-methacrylates of polyethylene glycols of molecular weight 200-500,copolymerizable mixtures of acrylated monomers (see e.g. U.S. Pat. No.4,652,274), and acrylated oligomers (see e.g. U.S. Pat. No. 4,642,126);and vinyl compounds such as styrene, divinyl succinate, divinyl adipateand divinylphthalate; polyfunctional (meth)acrylates comprisingurethane, urea or amide groups. Mixtures of two or more of these freeradically polymerizable materials can be used if desired.

These ethylenically unsaturated monomers can be employed in the dentalcomposition(s) either alone or in combination with other ethylenicallyunsaturated monomers.

Monomers comprising a hydroxyl moiety can also be added. Suitablecompounds include 2-hydroxyethyl (meth)acrylate (HEMA), 2- or3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate,5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate,10-hydroxydecyl (meth)acrylate, dialkylene glycol mono(meth)acrylate,for example, diethylene glycol mono(meth)acrylate, triethylene glycolmono(meth)acrylate, tetraethylene glycol mono(meth)acrylate,polyethylene glycol mono(meth)acrylate, dipropylene glycolmono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and further1,2- or 1,3- and 2,3-dihydroxypropyl (meth)acrylate,2-hydroxypropyl-1,3-di(meth)acrylate,3-hydroxypropyl-1,2-di(meth)acrylate,N-(meth)acryloyl-1,2-dihydroxypropylamine,N-(meth)acryloyl-1,3-dihydroxypropylamine, adducts of phenol andglycidyl (meth)acrylate, for example, 1-phenoxy-2-hydroxypropyl(meth)acrylate, 1-naphthoxy-2-hydroxypropyl (meth)acrylate, bisphenol Adiglycidyl (meth)acrylate and the like, 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl (meth)acrylate and 2,3-dihydroxypropyl (meth)acrylateare particularly preferable.

If desired, mixtures of one or more of these components can be used.

Suitable polymerizable monomers with a urethane moiety also includethose having the structure A-(-S1-U—S2-MA)_(n) with

A being a connector element comprising at least one unit, S1 being aspacergroup comprising at least 4 units connected with each other, S2being a spacergroup comprising at least 4 units connected with eachother, the units of A, S1 and S2 being independently selected from CH₃—,—CH₂—, —O—, —S—, —NR¹—, —CO—, —CR¹═,

—N═, —CR¹R²—, with R¹ and R² independently selected from hydrogen,alkyl, substituted alkyl, alkenyl, cycloalkyl, substituted cycloalkyl,arylalkyl, aryl or substituted aryl, wherein these units can formlinear, branched or cyclic structures such as alkyl, cycloalkyl, aryl,ester, urethane or amide groups,

-   U being an urethane, urea or amide group connecting spacergroups S1    and S2,-   MA being an acrylate or methacrylate group and-   n being 3 to 6.

Specific examples of polymerizable monomers with urethane moietiesinclude:

Further examples are described in U.S. Pat. No. 8,329,776 B2 (Hecht etal.). The content of this reference is herewith incorporated byreference.

In addition or besides those components, other hardenable componentswhich can be added include oligomeric or polymeric compounds, such aspolyester urethane (meth)acrylates, polyether urethane (meth)acrylates,polycarbonate urethane (meth)acrylates and poly(meth)acrylate urethane(meth)acrylates. The molecular weight of these compounds is typicallyless than 20,000 g/mol, particularly less than 15,000 g/mol and inparticular less than 10,000 g/mol.

Adding these components may be used to adjust the rheologicalproperties.

Mixtures of two, three or more of the polymerizable monomers (3) can beused, if desired.

The polymerizable monomer (2) can be present in the following amounts:

-   -   Lower limit: at least about 0 or at least about 1 or at least        about 5 wt.-%,    -   Upper Limit: up to about 70 or up to about 60 or up to about 50        wt.-%,    -   Range: from about 0 to about 70 or from about 1 to about 60 or        from about 5 to about 50 wt.-%,        wt.-% with respect to the amount of the whole composition.

The composition described in the present text also comprises aninitiator. If more than one initiator component is required, theinitiator is also referred to as initiator system.

The nature of the initiator is not particularly limited, unless thedesired result cannot be achieved.

The initiator system can comprise systems which are capable ofinitiating polymerization via radiation (i.e. radiation curing), heat(i.e. heat curing), redox reaction (i.e. redox-curing) or a combinationthereof.

A class of initiators capable of initiating polymerization of thehardenable components of the resin matrix which contain free radicallyactive functional groups includes free radical-generatingphotoinitiators, optionally combined with a photosensitizer oraccelerator.

Such initiators typically can be capable of generating free radicals foraddition polymerization upon exposure to light energy having awavelength between about 200 and about 700 nm.

Initiator components which can undergo an alpha-cleavage are sometimespreferred.

Using acylphosphine oxides as initiators or part of the initiator systemwas found to be particularly useful.

Suitable acylphosphine oxides can be characterized by the followingformula

(R⁹)₂—P(═O)—C(═O)—R¹⁰

wherein each R⁹ individually can be a hydrocarbyl group such as alkyl,cycloalkyl, aryl, and aralkyl, any of which can be substituted with ahalo-, alkyl- or alkoxy-group, or the two R⁹ groups can be joined toform a ring along with the phosphorous atom, and wherein R¹⁰ is ahydrocarbyl group, an S-, O-, or N-containing five- or six-memberedheterocyclic group, or a —Z—C(═O)—P(═O)—(R⁹)₂ group, wherein Zrepresents a divalent hydrocarbyl group such as alkylene or phenylenehaving from 2 to 6 carbon atoms.Suitable systems are also described e.g. in U.S. Pat. No. 4,737,593, thecontent of which is herewith incorporated by reference.

Preferred acylphosphine oxides useful in the invention are those inwhich the R⁹ and R¹⁰ groups are phenyl or lower alkyl- or loweralkoxy-substituted phenyl. By “lower alkyl” and “lower alkoxy” is meantsuch groups having from 1 to 4 carbon atoms. Most preferably, theacylphosphine oxide is 2,4,6-trimethylbenzoyl diphenyl phosphine oxide(Lucirin™ TPO, BASF).

Suitable bisacylphosphine oxides can also be described by the followingformula

wherein n is 1 or 2, and R⁴, R⁵, R⁶ and R⁷ are H, C1-4 alkyl, C1-4alkoxyl, F, Cl or Br; R² and R³, which are the same or different,standfor a cyclohexyl, cyclopentyl, phenyl, naphthyl, or biphenylyl radical,a cyclopentyl, cyclohexyl, phenyl, naphthyl, or biphenylyl radicalsubstituted by F, Cl, Br, I, C1-4 alkyl and/or C1-4 alkoxyl, or an S orN-containing 5-membered or 6-membered heterocyclic ring; or R² and R³are joined to form a ring containing from 4 to 10 carbon atoms and beingoptionally substituted by 1 to 6 C1-4 alkyl radicals.

More specific examples include: bis-(2,6-dichlorobenzoyl)phenylphosphineoxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide,bis-(2,6-dichlorobenzoyl)-4-ethoxyphenylphosphine oxide,bis-(2,6-dichlorobenzoyl)-4-biphenylylphosphine oxide,bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide,bis-(2,6-dichlorobenzoyl)-2-naphthylphosphine oxide,bis-(2,6-dichlorobenzoyl)-1-napthylphosphine oxide,bis-(2,6-dichlorobenzoyl)-4-chlorophenylphosphine oxide,bis-(2,6-dichlorobenzoyl)-2,4-dimethoxyphenylphosphine oxide,bis-(2,6-dichlorobenzoyl)decylphosphine oxide,bis-(2,6-dichlorobenzoyl)-4-octylphenylphosphine oxide,bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide,bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide,bis-(2,4,6-trimethylbenzoyl)-2,5-dimethylphenylphosphine oxide,bis-(2,6-dichloro-3,4,5-trimethoxybenzoyl)-2,5-dimethylphenylphosphineoxide,bis-(2,6-dichloro-3,4,5-trimethoxybenzoyl)-4-ethoxyphenylphosphineoxide, bis-(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide,bis-(2-methyl-1-naphthoyl)phenylphosphine oxide.bis-(2-methyl-1-naphthoyl)-4-biphenylylphosphine oxide,bis-(2-methyl-1-naphthoyl)-4-ethoxyphenylphosphine oxide,bis-(2-methyl-1-naphthoyl)-2-naphthylphosphine oxide,bis-(2-methyl-1-naphthoyl)-4-propylphenylphosphine oxide,bis-(2-methyl-1-naphthoyl)-2,5-dimethylphosphine oxide,bis-(2-methoxy-1-naphthoyl)-4-ethoxyphenylphosphine oxide,bis-(2-methoxy-1-naphthoyl)-4-biphenylylphosphine oxide,bis-(2-methoxy-1-naphthoyl)-2-naphthylphosphine oxide andbis-(2-chloro-1-naphthoyl)-2,5-dimethylphenylphosphine oxide.

The acylphosphine oxide bis(2,4,6-trimethylbenzoyl)phenyl phosphineoxide (IRGACURE™ 819, Ciba Specialty Chemicals, Tarrytown, N.Y.) issometimes preferred.

Tertiary amine reducing agents may be used in combination with anacylphosphine oxide. Illustrative tertiary amines useful in theinvention include ethyl 4-(N,N-dimethyl-amino)benzoate (EDMAB) andN,N-dimethylaminoethyl methacrylate (DMAEMA).

Commercially-available phosphine oxide photoinitiators capable offree-radical initiation when irradiated at wavelengths of greater than400 nm to 1200 nm include a 25:75 mixture, by weight, ofbis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide and2-hydroxy-2-methyl-1-phenylpropan-1-one (IRGACURE™ 1700, Ciba SpecialtyChemicals),2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholinophenyl)-1-butanone(IRGACURE™ 369, Ciba Specialty Chemicals),bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium (IRGACURE™ 784 DC, Ciba Specialty Chemicals), a 1:1 mixture, byweight, of bis(2,4,6-trimethylbenzoyl)phenyl phosphine oxide and2-hydroxy-2-methyl-1-phenylpropane-1-one (DAROCUR™ 4265, Ciba SpecialtyChemicals), and ethyl-2,4,6-trimethylbenzylphenyl phosphinate (LUCIRIN™LR8893X, BASF Corp., Charlotte, N.C.).

A variety of visible or near-IR photoinitiator systems may also be usedfor photopolymerization of free-radically polymerizable materials.

For example, a photoinitiation system can be used selected from systemswhich initiate polymerization via a two component system of an amine andan α-diketone. Such systems are described e.g. in U.S. Pat. No.4,071,424 and WO 2009151957, which are herein incorporated by reference.

Alternatively, the resin can be combined with a three components orternary photoinitiator system. Suitable systems are described in U.S.Pat. No. 5,545,676 and WO 2009151957, which are incorporated herein byreference.

In the ternary photoinitator system, the first component is an iodoniumsalt, i.e., a diaryliodonium salt. The iodonium salt is preferablysoluble in the monomer and shelf-stable (i e., does not spontaneouslypromote polymerization) when dissolved therein in the presence of thesensitizer and donor. Accordingly, selection of a particular iodoniumsalt may depend to some extent upon the particular monomer, polymer oroligomer, sensitizer and donor chosen. Suitable iodonium salts aredescribed in U.S. Pat. No. 3,729,313, U.S. Pat. No. 3,741,769, U.S. Pat.No. 3,808,006, U.S. Pat. No. 4,250,053 and U.S. Pat. No. 4,394,403, theiodonium salt disclosures of which are incorporated herein by reference.The iodonium salt can be a simple salt (e.g., containing an anion suchas Cl⁻, Br⁻, I⁻ or C₄H₅ SO₃ ⁻) or a metal complex salt (e.g., containingSbF₅OH⁻ or AsF₆ ⁻). Mixtures of iodonium salts can be used if desired.Preferred iodonium salts include diphenyliodonium salts such asdiphenyliodonium chloride, diphenyliodonium hexafluorophosphate anddiphenyliodonium tetrafluoroborate.

The second component in a ternary photoinitiator system is a sensitizer.The sensitizer desirably is soluble in the monomer, and is capable oflight absorption somewhere within the range of wavelengths of greaterthan 400 to 1200 nanometers, more preferably greater than 400 to 700nanometers and most preferably greater than 400 to about 600 nanometers.The sensitizer may also be capable of sensitizing2-methyl-4,6-bis(trichloromethyl)-s-triazine, using the test proceduredescribed in U.S. Pat. No. 3,729,313, which is incorporated herein byreference. Preferably, in addition to passing this test, a sensitizer isalso selected based in part upon shelf stability considerations.Accordingly, selection of a particular sensitizer may depend to someextent upon the particular monomer, oligomer or polymer, iodonium saltand donor chosen.

Suitable sensitizers can include compounds in the following categories:ketones, coumarin dyes (e.g., ketocoumarins), xanthene dyes, acridinedyes, thiazole dyes, thiazine dyes, oxazine dyes, azine dyes,aminoketone dyes, porphyrins, aromatic polycyclic hydrocarbons,p-substituted aminostyryl ketone compounds, aminotriaryl methanes,merocyanines, squarylium dyes and pyridinium dyes. Ketones (e.g.,monoketones or alpha-diketones), ketocoumarins, aminoarylketones andp-substituted aminostyryl ketone compounds are preferred sensitizers.For applications requiring high sensitivity, it is preferred to employ asensitizer containing a julolidinyl moiety. For applications requiringdeep cure (e.g., cure of highly-filled composites), it is preferred toemploy sensitizers having an extinction coefficient below about 1000,more preferably below about 100, at the desired wavelength ofirradiation for photopolymerization. Alternatively, dyes that exhibitreduction in light absorption at the excitation wavelength uponirradiation can be used.

For example, a preferred class of ketone sensitizers has the formula:ACO(X)_(b)B, where X is CO or CR⁵R⁶, where R⁵ and R⁶ can be the same ordifferent, and can be hydrogen, alkyl, alkaryl or aralkyl, b is zero orone, and A and B can be the same or different substituted (having one ormore non-interfering substituents) or unsubstituted aryl, alkyl,alkaryl, or aralkyl groups, or together A and B can form a cyclicstructure which can be a substituted or unsubstituted cycloaliphatic,aromatic, heteroaromatic or fused aromatic ring.

Suitable ketones of the above formula include monoketones (b=0) such as2,2-, 4,4- or 2,4-dihydroxybenzophenone, di-2-pyridyl ketone,di-2-furanyl ketone, di-2-thiophenyl ketone, benzoin, fluorenone,chalcone, Michler's ketone, 2-fluoro-9-fluorenone, 2-chlorothioxanthone,acetophenone, benzophenone, 1- or 2-acetonaphthone, 9-acetylanthracene,2-, 3- or 9-acetylphenanthrene, 4-acetylbiphenyl, propiophenone,n-butyrophenone, valerophenone, 2-, 3- or 4-acetylpyridine,3-acetylcoumarin and the like. Suitable diketones includearalkyldiketones such as anthraquinone, phenanthrenequinone, o-, m- andp-diacetylbenzene, 1,3-, 1,4-, 1,5-, 1,6-, 1,7- and1,8-diacetylnaphthalene, 1,5-, 1,8- and 9,10-diacetylanthracene, and thelike. Suitable alpha-diketones (b=1 and X═CO) include 2,3-butanedione,2,3-pentanedione, 2,3-hexanedione, 3,4-hexanedione, 2,3-heptanedione,3,4-heptanedione, 2,3-octanedione, 4,5-octanedione, benzil, 2,2′-3 3′-and 4,4′-dihydroxylbenzil, furil, di-3,3′-indolylethanedione,2,3-bornanedione (camphorquinone), biacetyl, 1,2-cyclohexanedione,1,2-naphthaquinone, acenaphthaquinone, and the like.

The third component of a ternary initiator system is a donor. Preferreddonors include, for example, amines (including aminoaldehydes andaminosilanes), amides (including phosphoramides), ethers (includingthioethers), ureas (including thioureas), ferrocene, sulfinic acids andtheir salts, salts of ferrocyanide, ascorbic acid and its salts,dithiocarbamic acid and its salts, salts of xanthates, salts of ethylenediamine tetraacetic acid and salts of tetraphenylboronic acid. The donorcan be unsubstituted or substituted with one or more non-interferingsubstituents. Particularly preferred donors contain an electron donoratom such as a nitrogen, oxygen, phosphorus, or sulfur atom, and anabstractable hydrogen atom bonded to a carbon or silicon atom alpha tothe electron donor atom. A wide variety of donors is disclosed in U.S.Pat. No. 5,545,676, which is incorporated herein by reference.

Another free-radical initiator system that can alternatively be used inthe dental compositions described in the present text is the class ofionic dye counterion complex initiators comprising a borate anion and acomplementary cationic dye.

Borate salt photoinitiators are described, for example, in U.S. Pat. No.4,772,530, U.S. Pat. No. 4,954,414, U.S. Pat. No. 4,874,450, U.S. Pat.No. 5,055,372, and U.S. Pat. No. 5,057,393, the disclosures of which areincorporated herein by reference.

Borate anions useful in these photointiators generally can be of theformula R¹R²R³R⁴B⁻, wherein R¹, R², R³, and R⁴ independently can bealkyl, aryl, alkaryl, allyl, aralkyl, alkenyl, alkynyl, alicyclic andsaturated or unsaturated heterocyclic groups. Preferably, R², R³, and R⁴are aryl groups and more preferably phenyl groups, and R¹ is an alkylgroup and more preferably a secondary alkyl group.

Cationic counterions can be cationic dyes, quaternary ammonium groups,transition metal coordination complexes, and the like. Cationic dyesuseful as counterions can be cationic methine, polymethine,triarylmethine, indoline, thiazine, xanthene, oxazine or acridine dyes.More specifically, the dyes may be cationic cyanine, carbocyanine,hemicyanine, rhodamine, and azomethine dyes. Specific examples of usefulcationic dyes include Methylene Blue, Safranine O, and Malachite Green.Quaternary ammonium groups useful as counterions can betrimethylcetylammonium, cetylpyridinium, and tetramethylammonium. Otherorganophilic cations can include pyridinium, phosphonium, and sulfonium.

Photosensitive transition metal coordination complexes that may be usedinclude complexes of cobalt, ruthenium, osmium, zinc, iron, and iridiumwith ligands such as pyridine, 2,2′-bipyridine,4,4′-dimethyl-2,2′-bipyridine, 1,10-phenanthroline,3,4,7,8-tetramethylphenanthroline, 2,4,6-tri(2-pyridyl-s-triazine) andrelated ligands.

Yet another alternative class of initiators capable of initiatingpolymerization of free radically active functional groups includesconventional chemical initiator systems such as a combination of aperoxide and an activator such as an amine. These initiators, which relyupon a thermal redox reaction, are often referred to as “auto-curecatalysts.” They are typically supplied as two-part systems in which thereactants are stored apart from each other and then combined immediatelyprior to use.

In particular, compounds such as lauroyl peroxide, benzoyl peroxide andp-chlorobenzoyl peroxide and p-methylbenzoyl peroxide can be consideredas organic peroxide compounds.

Suitable as activators are, for example, tertiary aromatic amines, suchas the N,N-bis-(hydroxyalkyl)-3,5-xylidines known from U.S. Pat. No.3,541,068 as well as N,N-bis-(hydroxyalkyl)-3,5-di-t-butylanilines, inparticular N,N-bis-([beta]-oxybutyl)-3,5-di-t-butylaniline as well asN,N-bis-(hydroxyalkyl)-3,4,5-trimethylaniline.

Well-suited activators are also the barbituric acids and barbituric acidderivatives as described in US 2003/008967, DE 14 95 520 as well as themalonyl sulfamides described in U.S. Pat. No. 4,544,742 (correspondingto EP 0 059 451). Preferred malonyl sulfamides are2,6-dimethyl-4-isobutylmalonyl sulfamide, 2,6-diisobutyl-4-propylmalonylsulfamide, 2,6-dibutyl4-propylmalonyl sulfamide,2,6-dimethyl4-ethylmalonyl sulfamide and 2,6-dioctyl4-isobutyl malonylsulfamide.

For further acceleration, the polymerization is in this case preferablycarried out in the presence of heavy-metal compounds and ionogenichalogen or pseudohalogen. The heavy metal is suitably used in the formof soluble organic compounds. Likewise, the halide and pseudohalide ionsare suitably used in the form of soluble salts, as examples there can benamed the soluble amine hydrochlorides as well as quarternary ammoniumchloride compounds. Suitable accelerators are in particular metals fromthe iron or copper group, preferably copper and iron complexes and inparticular copper complexes. The heavy metal is preferably employed inthe form of soluble organic compounds. Suitable are, for example, ironcarboxylates, copper carboxylates, iron procetonate, copper procetonate,copper naphthenate, copper acetate and iron naphthenate.

In a further alternative, heat may be used to initiate the hardening, orpolymerization, of free radically active groups. Examples of heatsources suitable for the dental materials described in the present textinclude inductive, convective, and radiant. Thermal sources should becapable of generating temperatures of at least 40° C. to 15° C. Thisprocedure is sometime preferred for initiating polymerization ofmaterials occurring outside of the oral environment.

Yet another alternative class of initiators capable of initiatingpolymerization of free radically active functional groups that areuseful for the dental materials as described in the present text arethose that include free radical-generating thermal initiators. Examplesinclude peroxides such as, for example, benzoyl peroxide and laurylperoxide, and azo compounds such as, for example,2,2-azobis-isobutyronitrile (AIBN).

If the color of the cured composition matters, an initiator system whichdoes not lead to undesired discoloration should be used. It was foundthat an initiator system comprising the following components isparticularly useful: monoacylphosphine oxides and/or bisacylphosphineoxides.

The initiator or initiator system is typically contained in thefollowing amounts:

-   -   Lower limit: at least about 0.1 or at least about 0.2 or at        least about 0.3 wt.-%,    -   Upper Limit: up to about 10 or up to about 8 or up to about 6        wt.-%,    -   Range: from about 0.1 to about 10 or from about 0.2 to about 8        or from about 0.3 to about 6 wt.-%,        wt.-% with respect to the amount of the whole composition.

The composition described in the present text also comprises filler.

Adding a filler can be beneficial e.g. for adjusting the rheologicalproperties like viscosity. The content of the filler also typicallyinfluences the physical properties of the composition after hardening,like hardness or flexural strength.

The chemical nature of the filler(s) is not particularly limited unlessthe intended purpose cannot be achieved.

The size of the filler particles should be such that a homogeneousmixture with the hardenable component forming the resin matrix can beobtained.

The particle size of the filler may be in a range from about 0.001 toabout 10 μm.

The filler(s) typically comprise non acid reactive fillers. A non-acidreactive filler is a filler which does not undergo an acid/base reactionwith an acid.

Useful non acid reactive fillers include fumed silica, quartz, groundglasses, non-water-soluble fluorides such as CaF₂, silica gels such assilicic acid, in particular pyrogenic silicic acid and granulatesthereof, cristobalite, calcium silicate, zirconium silicate, zeolites,including the molecular sieves, barium sulphate, yttrium fluoride.

Suitable fumed silicas include for example, products sold under thetradename Aerosil™ series OX-50, -130, -150, and -200, Aerosil R8200available from Degussa AG, (Hanau, Germany), CAB-O-SIL™ M5 availablefrom Cabot Corp (Tuscola, Ill.), and HDK types, e.g. HDK-H 2000, HDKH15; HDK H18, HDK H2O and HDK H30 available from Wacker.

The average surface area of the silica particles is preferably greaterthan about 15 m²/g more preferably greater than about 30 m²/g.

Filler(s) which can also be used include nano-sized fillers such asnano-sized silica.

Suitable nano-sized particles typically have a mean particle size in therange of about 5 to about 80 nm.

Preferred nano-sized silicas are commercially available from NalcoChemical Co. (Naperville, Ill.) under the product designation NALCOCOLLOIDAL SILICAS (for example, preferred silica particles can beobtained from using NALCO products 1040, 1042, 1050, 1060, 2327 and2329), Nissan Chemical America Company, Houston, Tex. (for example,SNOWTEX-ZL, -OL, -O, -N, -C, -20L, -40, and -50); Admatechs Co., Ltd.,Japan (for example, SX009-MIE, SX009-MIF, SC1050-MJM, and SC1050-MLV);Grace GmbH & Co. KG, Worms, Germany (for example, those available underthe product designation LUDOX, e.g., P-W50, P-W30, P-X30, P-T40 andP-T40AS); Akzo Nobel Chemicals GmbH, Leverkusen, Germany (for example,those available under the product designation LEVASIL, e.g., 50/50%,100/45%, 200/30%, 200A/30%, 200/40%, 200A/40%, 300/30% and 500/15%), andBayer MaterialScience AG, Leverkusen, Germany (for example, thoseavailable under the product designation DISPERCOLL S, e.g., 5005, 4510,4020 and 3030).

Surface-treating the nano-sized silica particles before loading into thedental material can provide a more stable dispersion in the resin.Preferably, the surface-treatment stabilizes the nano-sized particles sothat the particles will be well dispersed in the hardenable resin andresults in a substantially homogeneous composition. Furthermore, it ispreferred that the silica be modified over at least a portion of itssurface with a surface treatment agent so that the stabilized particlecan copolymerize or otherwise react with the hardenable resin duringcuring.

Thus, the silica particles as well as other suitable non acid-reactivefillers can be treated with a resin-compatibilizing surface treatmentagent.

Particularly preferred surface treatment or surface modifying agentsinclude silane treatment agents capable of polymerizing with a resin.Preferred silane treatment agent includegamma-methacryloxylpropyltrimethoxysilane, available commercially underthe trade designation A-174, available commercially from Witco OSiSpecialties (Danbury, Conn.) and gamma-glycidoxypropyltrimethoxy silane,a product available under the trade designation G6720, available fromUnited Chemical Technologies (Bristol, Pa.).

Alternatively a combination of surface modifying agents can be useful,wherein at least one of the agents has a functional groupco-polymerizable with a hardenable resin.

For example, the polymerizing group can be ethylenically unsaturated ora cyclic function subject to ring opening polymerization. Anethylenically unsaturated polymerizing group can be, for example, anacrylate or methacrylate, or vinyl group. A cyclic functional groupsubject to ring opening polymerization generally contains a heteroatomsuch as oxygen, sulfur or nitrogen, and preferably is a 3-membered ringcontaining oxygen such as an epoxide. Other surface modifying agentswhich do not generally react with hardenable resins can be included toenhance dispersibility or rheological properties. Examples of silane ofthis type include, for example, alkyl or aryl polyethers, alkyl, hydroxyalkyl, hydroxy aryl, or amino alkyl functional silanes.

Besides an inorganic material the filler(s) can also be based on anorganic material. Examples of suitable organic filler particles includefilled or unfilled pulverized polycarbonates, poly(meth)acrylates,polyepoxides, and the like.

If desired, the measurement of the particle size of the filler particlescan be done with a TEM (transmission electron microscopy) method,whereby a population is analyzed to obtain an average particle diameter.

A preferred method for measuring the particle diameter can be describedis as follows:

Samples approximately 80 nm thick are placed on 200 mesh copper gridswith carbon stabilized formvar substrates (SPI Supplies—a division ofStructure Probe, Inc., West Chester, Pa.). A transmission electronmicrograph (TEM) is taken, using JEOL 200CX (JEOL, Ltd. of Akishima,Japan and sold by JEOL USA, Inc.) at 200 Kv. A population size of about50-100 particles can be measured and an average diameter is determined.

The amount of filler to be used in the filler matrix usually depends onthe purpose for which the composition should be used.

The filler is typically used in the following amounts:

-   -   Lower limit: at least about 20 or at least about 30 or at least        about 40 wt.-%,    -   Upper Limit: up to about 95 or up to about 90 or up to about 85        wt.-%,    -   Range: from about 20 to about 95 or from about 30 to about 90 or        from about 40 to about 85 wt.-%,        wt.-% with respect to the amount of the whole composition.

The adhesive composition described in the present text may also compriseadditives.

Besides the above mentioned components, the dental composition describedin the present text may further contain one, two or more of thefollowing additives:

-   -   x-ray visible particles,    -   pigments,    -   photobleachable colorants,    -   fluoride release agents,    -   stabilizers,    -   retarders,        and mixtures thereof.

Suitable x-ray visible particles which may be present include particlesof metal oxides like the oxides of yttrium, ytterbium, strontium,barium, zirconium, hafnium, niobium, tantalum, tungsten, bismuth,molybdenum, tin, zinc, lanthanide elements (i.e.

elements having atomic numbers ranging from 57 to 71, inclusive), ceriumand combinations thereof. Most preferably, the oxides of heavy metalshaving an atomic number greater than 30, but less than 72 are optionallyincluded in the materials of the invention. Particularly preferredradiopacifying metal oxides include lanthanum oxide, zinc oxide, tinoxide, zirconium oxide, yttrium oxide, ytterbium oxide, barium oxide,strontium oxide, cerium oxide, and combinations thereof.

Examples of pigments, which can be used include titanium dioxide or zincsulphide (lithopones), red iron oxide 3395, Bayferrox 920 Z Yellow,Neazopon Blue 807 (copper phthalocyanine-based dye) or Helio Fast YellowER. These additives may be used for individual coloring of the dentalcompositions.

Examples of photobleachable colorants which can be present include RoseBengal, Methylene Violet, Methylene Blue, Fluorescein, Eosin Yellow,Eosin Y, Ethyl Eosin, Eosin bluish, Eosin B, Erythrosin B, ErythrosinYellowish Blend, Toluidine Blue, 4′,5′-Dibromofluorescein and blendsthereof. Further examples of photobleachable colorants can be found inU.S. Pat. No. 6,444,725. The color of the compositions of the inventionmay be additionally imparted by a sensitizing compound.

Examples of fluoride release agents which can be present includenaturally occurring or synthetic fluoride minerals. These fluoridesources can optionally be treated with surface treatment agents.

Further additives, which can be added, include stabilizers, especiallyfree radical scavengers such as substituted and/or unsubstitutedhydroxyaromatics (e.g. butylated hydroxytoluene (BHT), hydroquinone,hydroquinone monomethyl ether (MEHQ), 3,5-di-tert-butyl-4-hydroxyanisole(2,6-di-tert-butyl-4-ethoxyphenol),2,6-di-tert-butyl-4-(dimethylamino)methylphenol or 2,5-di-tert-butylhydroquinone, 2-(2′-hydroxy-5′-methylphenyl)-2H-benzotriazole,2-(2′-hydroxy-5′-t-octylphenyl)-2H-benzotriazole,2-hydroxy-4-methoxybenzophenone (UV-9),2-(2′-hydroxy-4′,6′-di-tert-pentylphenyl)-2H-benzotriazole,2-hydroxy-4-n-octoxybenzophenone,2-(2′-hydroxy-5′-methacryloxyethylphenyl)-2H-benzotriazole,phenothiazine, and HALS (hindered amine light stabilizers).

Further additives, which can be added, include retarders, (such as1,2-diphenylethylene), plasticizers (including polyethylene glycolderivatives, polypropylene glycols, low-molecular-weight polyesters,dibutyl, dioctyl, dinonyl and diphenyl phthalate, di(isononyl adipate),tricresyl phosphate, paraffin oils, glycerol triacetate, bisphenol Adiacetate, ethoxylated bisphenol A diacetate, and silicone oils),flavorants, anti-microbials, fragrance, agents that impart fluorescenceand/or opalescence and fluoride releasing materials.

There is no need for the additive(s) to be present. The additive(s) maybe present in the following amounts:

-   -   Lower limit: at least about 0 or at least about 0.1 or at least        about 1 wt.-%,    -   Upper Limit: up to about 10 or up to about 8 or up to about 5        wt.-%,    -   Range: from about 0 to about 10 or from about 0.1 to about 8 or        from about 1 to about 5 wt.-%,        wt.-% with respect to the amount of the whole composition.

According to a further embodiment, the dental composition described inthe present text is described as follows:

-   -   Polymerizable monomer (1): from about 1 to about 75 wt.-%, or        from about 5 to about 70 wt.-%, or from about 10 to about 65        wt.-%;    -   Polymerizable monomer (2): from about 0 to about 60 wt.-%, or        from about 0.1 to about 50 wt.-%, or from about 1 to about 40        wt.-%;    -   Polymerizable monomer (3): from 0 to about 70 wt.-%, or from        about 1 to about 60 wt.-%, or from about 5 to about 50 wt.-%;    -   Initiator(s): from about 0.1 to about 10 wt.-%, or from about        0.2 to about 8 wt.-%, or from about 0.3 to about 6 wt.-%;    -   Filler(s): from about 20 to about 95 wt.-%, or from about 30 to        about 90 wt.-%, or from about 40 to about 85 wt.-%;    -   Additive(s): from 0 to about 10 wt.-%, or from about 0.1 to        about 8 wt.-%, or from about 1 to about 5 wt.-%;        wt.-% with respect to the weight of the whole composition.

The dental composition described in the present text can be produced asfollows:

-   -   providing the respective components,    -   mixing the components.

Mixing can be achieved by using any means known to the practitioner.That is, the adhesive composition can be prepared in an one-potsynthesis simply by putting the respective components together andmixing them.

If desired, the production process is performed under save lightconditions to avoid an undesired polymerization of the composition.

The hardenable dental composition described in the present text istypically stored in a container until use. Depending on the formulationand the curing status, various containers can be used.

The composition can be provided in the form of a one-component system oras a two-component system. This typically depends on the initiatorsystem chosen. If the composition is redox curable or curing, it isusually provided as a two-component system.

If the dental composition is provided as a one-component system, it canbe stored in a container having only one chamber such as a compule orscrew tube.

A compule typically has a cylindrical housing with a front and a rearend and a nozzle. The rear end of the housing is usually sealed with amovable piston. Typically, the dental composition is dispensed out ofthe compule or container using an applier having a movable plunger (e.g.an application device having the shape of a caulk gun). Examples ofsuitable compules or containers are described in U.S. Pat. No.5,624,260, EP 1 340 472 A1, US 2007/0172789 A1, U.S. Pat. No. 5,893,714and U.S. Pat. No. 5,865,803, the content of which with regard to thedescription of compules or containers is herewith incorporated byreference.

Suitable two-component systems for storage include two-barrelcartridges.

Suitable two-component systems are described e.g. in US 2007/0090079 orU.S. Pat. No. 5,918,772. The content of these documents with respect tothe description of the vial or bottle is herewith incorporated byreference. Cartridges which can be used are also commercially availablefrom SulzerMixpac AG (Switzerland).

The volume of each compartment of the two-barrel cartridges is typicallyin the range from about 0.1 to about 100 ml or from about 0.5 to about50 ml or from about 1 to about 30 ml.

The volume ratio of compartment (I) to compartment (II) is typicallywithin a range of about 1:1 to about 10:1.

Static mixing tips which can be used for mixing the compositionscontained in the compartments are described e.g. in US 2006/0187752 orin U.S. Pat. No. 5,944,419. The disclosure of these patents is herewithincorporated by reference. Mixing tips which can also be used arecommercially available from SulzerMixpac AG (Switzerland).

If the dental composition is provided in the form of a dental millblank, it is typically fixed to a holding device including frames ormandrels.

The invention described in the present text is also directed to a kit ofparts.

Such a kit typically comprises the dental composition described in thepresent text, a dental adhesive and/or a dental cement, optionally anapplicator and optionally an instruction of use.

The instruction of use typically contains hints to the practitioner howand under what conditions the adhesive composition should be applied tothe surface of hard dental tissue.

The dental composition can be used as or for producing a dental fillingmaterial, dental cement, dental crown or bridge material or dental millblank.

The dental composition is typically used in the mouth of a patient andis disposed adjacent to natural teeth. The phrase “disposed adjacent to”as used herein refers to the placing of a dental material in temporaryor permanent (e.g., occlusal or proximal) contact with a natural tooth.

The term “composite” as used herein in the context of a dental materialrefers to a filled dental material. The term “restorative” as usedherein refers to a dental composite that is polymerized after it isdisposed adjacent to a tooth. The term “prosthesis” as used hereinrefers to a composite that is shaped and polymerized for its final use(e.g., as a crown, bridge, veneer, inlay, onlay or the like) before itis disposed adjacent to a tooth.

A typical application process for the composition described in thepresent text to be used as a restorative composite typically includesthe following steps in the desired order:

-   -   providing the composition,    -   placing the composition in contact with hard dental tissue,        especially the surface thereof,    -   curing the composition, e.g. by applying radiation (e.g. visible        light) to the composition for a period of time sufficient to        initiate the polymerisation process (e.g. about 5 to about 20        s).

Suitable tools for applying radiation include dental curing lights.Suitable dental curing lights are described e.g. in US 2005/0236586. Thecontent of this document is herewith incorporated by reference. Suitabledental curing lights are also commercially available e.g. under thetrade names Elipar™ S10 (3M ESPE).

The dental composition described in the present text can also be usedfor producing a dental crown, bridge, onlay or inlay outside the mouthof a patient.

The production can be done either by a so-called constructive approach(i.e. build-up approach) or by a so-called destructive approach (i.e.machining or milling approach).

The build-up approach can be performed by any means known to the skilledperson including rapid-prototyping techniques.

Rapid-prototyping techniques include ink jet printing, 3d-printing,robo-casting, laminated object manufacturing, stereolithography,photostereolithography, or combinations thereof.

A suitable example for a suitable process is described e.g. in US2012/068388 (3M). The content of this reference is herewith incorporatedby reference.

The machining approach can also be performed by any means known to theskilled person including milling the desired dental restoration out of adental mill blank.

If desired, the dental mill blank can be attached to a holding device.Suitable holding devices include frames and stubs or mandrels. Sometimesit can be desirable, if the dental mill blank is put in a magazine,either for storing or for machining The holding device typicallyfacilitates the machining of the dental article, e.g. by using amachining or milling device.

Examples of holding devices are shown in US 2003/0132539, U.S. Pat. No.6,769,912 and EP 0 455 854 B1. The content of these documents withregard to holding devices (e.g. frames and stubs or supporting body) isherewith incorporated by reference and regarded part of the text of thepresent invention.

Fixing of the dental mill blank to the holding device can be achievede.g. by gluing. The fixing should be such that the dental milling blankcan be processed in a milling machine.

Besides gluing other means for attaching the holding device includebonding, screwing, and combinations thereof.

Thus, a further embodiment of the present invention is directed to aprocess for producing a dental mill blank, the process comprising thesteps of

-   -   providing a dental composition as described in the present text,        the dental composition being in its uncured state,    -   hardening or curing the dental composition to obtain a hardened        or cured dental composition,    -   optionally fixing the hardened dental composition to a holding        device, the dental composition being provided in the shape of a        dental mill blank.

The dental mill blank can be produced by placing the curable dentalcomposition into a mould followed by a curing step.

Another option for producing a dental mill blank is to apply a build-upor layer technique. In that case, the dental composition is typicallyprovided in the form of a flat layer, the layer is cured and a furthercurable layer of the dental composition is applied on top of theprevious layer followed by a further curing step. These steps arerepeated until the object has the desired dimensions.

Yet, a further embodiment of the present invention is directed to aprocess for producing a dental restoration, the process comprising thesteps of

-   -   providing a dental mill blank as described in the present text,        the dental mill blank comprising the dental composition        described in the present text, the dental composition being in        its cured state,    -   machining the dental mill blank to obtain a dental restoration,        the dental restoration having typically the shape of a dental        crown, bridge, inlay or veneer.

According to a particular embodiment, the dental composition describedin the present text is characterized as follows:

-   -   Polymerizable monomer(s) (1) being represented by a formula as        described in the text above with respect to the polymerizable        monomer (1) in an amount from about 1 to about 75 wt.-%,    -   Initiator(s) being selected from radiation curing or redox        curing initiators,    -   Silica or silica/zirconia filler(s) from about 20 to about 95        wt.-%.

All components used in the dental composition of the invention should besufficiently biocompatible, that is, the composition should not producea toxic, injurious, or immunological response in living tissue.

According to one embodiment, the dental composition described in thepresent text does not contain or is essentially free of either or moreor all of the following components: Solvent(s) selected from water oralcohol(s) (e.g. ethanol) or combinations thereof in an amount of morethan about 5 or 10 or 20 wt.-%, wt.-% with respect to the weight of thewhole composition.

The complete disclosures of the patents, patent documents, andpublications cited herein are incorporated by reference in theirentirety as if each were individually incorporated. Variousmodifications and alterations to this invention will become apparent tothose skilled in the art without departing from the scope and spirit ofthis invention. The above specification, examples and data provide adescription of the manufacture and use of the compositions and methodsof the invention. The invention is not limited to the embodimentsdisclosed herein. One skilled in the art will appreciate that manyalternative embodiments of the invention can be made without departingfrom the spirit and scope of thereof.

The following examples are given to illustrate, but not limit, the scopeof this invention. Unless otherwise indicated, all parts and percentagesare by weight.

EXAMPLES

Unless otherwise indicated, all parts and percentages are on a weightbasis, all water is deionized water, and all molecular weights areweight average molecular weight. Moreover, unless otherwise indicatedall Experiments were conducted at ambient conditions (23° C.; 1013mbar). Moreover, nearly all process steps are conducted under anatmosphere of dry air:

Compressive Strength 1 (CS 1)

If desired, the measurement of the compressive strength 1 can be carriedout according to ISO 4049 using specimens having the dimension of 3 mm×3mm×5 mm. The compressive strength 1 is typically given in MPa.

Compressive Strength 2 (CS 2)

If desired, the measurement of the compressive strength 2 can be carriedout according to DIN 53454 (ISO 9917 2001) using cylindrical specimenswith a diameter of 4 mm and a height of 8 mm. The compressive strength 2is typically given in MPa.

Abbreviations

The name and/or structure of the components used are given in Table 1.

TABLE 1 EBP-MA

CE1 Ethoxylated BisPhenol A dimethacrylate (m + n = 4), (ComparativeExample 1) OBP-MA

CE2 Oxetanylated BisPhenol A dimethacrylate (Comparative Example 2)ER-MA

CE3 Comparative Example 3 EH-MA

CE4 Comparative Example 4 E4R-MA

CE5 Comparative Example 5 OR-MA

CE6 Comparative Example 6 EER-A/MA/AM

IE1 R = H: EER-A, R = CH3: EER-MA (Inventive Example 1), R = 1x H/1xCH3: EER-AM EOR-A/MA/AM

R = H: EOR-A, R = CH3: EOR-MA, R = 1x H/1x CH3: EOR-AM OER-A/MA/AM

IE2 R = H: OER-A, R = CH3: OER-MA (Inventive Example 2), R = 1x H/1xCH3: OER-AM OOR-A/MA/AM

IE3 R = H: OOR-A, R = CH3: OOR-MA (Inventive Example 3), R = 1x H/1xCH3: OOR-AM OE2R-A/MA/AM

IE4 R = H: OE2R-A, R = CH3: OE2R-MA (Inventive Example 4), R = 1x H/1xCH3: OE2R-AM HOR-A/MA/AM

IE5, IE6 R = H: HOR-A, (Inventive Example 6), R = CH3: HOR-MA (InventiveExample 5), R = 1x H/1x CH3: HOR-AM POR-A/MA/AM

IE7 R = H: POR-A, R = CH3: POR-MA (Inventive Example 7), R = 1x H/1xCH3: POR-AM EEC-A/MA/AM

R = H: EEC-A, R = CH3: EEC-MA, R = 1x H/1x CH3: EEC-AM OE2C-A/MA/AM

IE8 R = H: OE2C-A, R = CH3: OE2C-MA (Inventive Example 8), R = 1x H/1xCH3: OE2C-AM E4RE-A/MA/AM

IE9 R = H: E4RE-A, R = CH3: E4RE-MA (Inventive Example 9), R = 1x H/1xCH3: E4RE-AM E4RH-A/MA/AM

IE10 R = H: E4RH-A, R = CH3: E4RH-MA (Inventive Example 10), R = 1x H/1xCH3: E4RH-AM ORE-A/MA/AM

IE11 R = H: ORE-A, R = CH3: ORE-MA (Inventive Example 11), R = 1x H/1xCH3: ORE-AM ORH-A/MA/AM

IE12 R = H: ORH-A, R = CH3: ORH-MA (Inventive Example 12), R = 1x H/1xCH3: ORH-AM EBC-A/MA/AM

IE13 R = H: EBC-A, R = CH3: EBC-MA (Inventive Example 13), R = 1x H/1xCH3: EBC-AM EEBC-A/MA/AM

IE14 R = H: EEBC-A, R = CH3: EEBC-MA (Inventive Example 14), R = 1x H/1xCH3: EEBC-AM E4BC-A/MA/AM

IE15 R = H: E4BC-A, R = CH3: E4BC-MA (Inventive Example 15), R = 1x H/1xCH3: E4BC-AM OBC-A/MA/AM

IE16 R = H: OBC-A, R = CH3: OBC-MA (Inventive Example 16), R = 1x H/1xCH3: OBC-AM OE2BC-A/MA/AM

IE17 R = H: OE2BC-A, R = CH3: OE2BC-MA (Inventive Example 17), R = 1xH/1x CH3: OE2BC-AM BC-GA/MA/AM

IE18 R = H: BC-GA, R = CH3: BC-GMA (Inventive Example 18), R = 1x H/1xCH3: BC-GAM PGS-A/MA/AM

R = H: PGS-A, R = CH3: PGS-MA, R = 1x H/1x CH3: PGS-AM PGiS-A/MA/AM

R = H: PGiS-A, R = CH3: PGiS-MA, R = 1x H/1x CH3: PGiS-AM PGT-A/MA/AM

IE19 R = H: PGT-A, R = CH3: PGT-MA, R = 1x H/1x CH3: PGT-AM (InventiveExample 19) EGS-A/MA/AM

R = H: EGS-A, R = CH3: EGS-MA, R = 1x H/1x CH3: EGS-AM EGiS-A/MA/AM

R = H: EGiS-A, R = CH3: EGiS-MA, R = 1x H/1x CH3: EGiS-AM ET-A/MA/AM

IE20 R = H: ET-A, R = CH3: ET-MA (Inventive Example 20), R = 1x H/1xCH3: ET-AM E2GS-A/MA/AM

R = H: E2GS-A, R = CH3: E2GS-MA, R = 1x H/1x CH3: E2GS-AM E2GiS-A/MA/AM

R = H: E2GiS-A, R = CH3: E2GiS-MA, R = 1x H/1x CH3: E2GiS-AM E2T-A/MA/AM

IE21 R = H: E2T-A, R = CH3: E2T-MA (Inventive Example 21), R = 1x H/1xCH3: E2T-AM OGS-A/MA/AM

R = H: OGS-A, R = CH3: OGS-MA, R = 1x H/1x CH3: OGS-AM OGiS-A/MA/AM

R = H: OGiS-A, R = CH3: OGiS-MA, R = 1x H/1x CH3: OGiS-AM OT-A/MA/AM

IE22 R = H: OT-A, R = CH3: OT-MA (Inventive Example 22), R = 1x H/1xCH3: OT-AM MGS-A/MA/AM

R = H: MGS-A, R = CH3: MGS-MA, R = 1x H/1x CH3: MGS-AM MGiS-A/MA/AM

R = H: MGiS-A, R = CH3: MGiS-MA, R = 1x H/1x CH3: MGiS-AM MGT-A/MA/AM

IE23 R = H: MGT-A, R = CH3: MGT-MA (Inventive Example 23), R = 1x H/1xCH3: MGT-AM O2oHB-A/MA/AM

R = H: O2oHB-A, R = CH3: O2oHB-MA, R = 1x H/1x CH3: O2oHB-AMOE2oHB-A/MA/AM

and

R = H: OE2oHB-A, R = CH3: OE2oHB-MA, R = 1x H/1x CH3: OE2oHB-AME4oHB-A/MA/AM

R = H: E4oHB-A, R = CH3: E4oHB-MA, R = 1x H/1x CH3: E4oHB-AMO2mHB-A/MA/AM

R = H: O2mHB-A, R = CH3: O2mHB-MA, R = 1x H/1x CH3: O2mHB-AMOE2mHB-A/MA/AM

and

R = H: OE2mHB-A, R = CH3: OE2mHB-MA, R = 1x H/1x CH3: OE2mHB-AME4mHB-A/MA/AM

R = H: E4mHB-A, R = CH3: E4mHB-MA, R = 1x H/1x CH3: E4mHB-AMO2pHB-A/MA/AM

R = H: O2pHB-A, R = CH3: O2pHB-MA, R = 1x H/1x CH3: O2pHB-AMOE2pHB-A/MA/AM

and

R = H: OE2pHB-A, R = CH3: OE2pHB-MA, R = 1x H/1x CH3: OE2pHB-AME4pHB-A/MA/AM

  R = H: E4pHB-A, R = CH3: E4pHB-MA, R = 1x H/1x CH3: E4pHB-AMResorcinol 1,3-dihydroxybenzene, CAS 108-46-3, EC 203-585-2 R Catechol1,2-dihydroxybenzene, CAS 120-80-9, EC 204-427-5 C Tert-butylcatechol4-tert-butylcatechol, 4-tert-butyl-1,2-dihydroxybenzene, CAS BC 98-29-3,EC 202-653-9 Tyrosol 4-(2-hydroxyethyl)phenol,2-(4-hydroxyphenyl)ethanol, CAS T 501-94-0, EC 207-930-8 Salicyl alcohol2-hydroxybenzyl alcohol, 2-hydroxymethylphenol, Saligenin, S CAS90-01-7, EC 201-960-5 iso-Salicyl alcohol 3-hydroxybenzyl alcohol,3-hydroxymethylphenol, CAS 620- iS 24-6, EC 210-633-6 Resorcinol3-hydroxyphenyl acetate, CAS 102-29-4, EC 203-022-0 RAc monoacetateResorcinol diacetate 1,3-diacetoxybenzene, CAS 108-58-7, EC 203-596-2RAc2 ortho- Salicylic acid, 2-hydroxybenzoic acid, CAS 69-72-7, EC 200-oHB Hydroxybenzoic 712-3 Acid meta- Iso-Salicylic acid, 3-hydroxybenzoicacid, CAS 99-06-9, EC mHB Hydroxybenzoic 202-726-5 Acid para-4-hydroxybenzoic acid, CAS 99-96-7, EC 202-804-9 pHB Hydroxybenzoic Acid2-chloroethanol Ethylene chlorohydrin, CAS 107-07-3, EC 203-459-73-chloro-1-propanol 1-chloro-3-hydroxypropane, CAS 627-30-5, EC210-992-9 2-(2-chloroethoxy) 3-oxa-5-chloro-1-pentanol, CAS 628-89-7, EC211-059-9 ethanol 5-chloro-1-pentanol Pentamethylene chlorohydrin, CAS5259-98-3, EC 226-067-8 6-chloro-1-hexanol Hexamethylene chlorohydrin,CAS 2009-83-8, EC 217-925-2 Ethylene carbonate 1,3-Dioxolan-2-one, CAS96-49-1, EC 202-510-0 Glycidyl phenyl 2-(phenoxymethyl)oxirane,2,3-epoxypropyl phenyl ether, GP ether phenyl glycidyl ether, CAS122-60-1, EC 204-557-2 Glycidyl 2,3-Epoxypropyl methacrylate,Methacrylic acid 2,3- GMA methacrylate epoxypropyl ester, CAS 106-91-2,EC 203-441-9 Acrylic acid Propenoic acid, CAS 79-10-7, EC 201-177-9 AAMethacrylic acid 2-Methacrylic acid, 2-Methylpropenoic acid, CAS79-41-4, MA EC 201-204-4 Methanesulfonic CAS 75-75-2, EC 200-898-6 MSAacid Tetrahydrofuran CAS 109-99-9, EC 203-726-8 THF iso-Propanol2-propanol, CAS 67-63-0, EC 200-661-7 IPA tert-Butanol2-methyl-2-propanol, CAS 75-65-0, EC 200-889-7 HOtBu Potassium tert-Potassium tert-butylate, CAS 865-47-4, EC 212-740-3 KOtBu butoxideSodium hydroxide CAS 1310-73-2, EC 215-185-5 NaOH Potassium hydroxideCAS 1310-58-3, EC 215-181-3 KOH Methyl tert-butyl tert-Butyl methylether, CAS 1634-04-4, EC 216-653-1 MTBE ether Ethyl acetate Acetic acidethyl ester, CAS 141-78-6, EC 205-500-4 EA Methyl ethyl Ethyl methylketone, 2-butanone, CAS 78-93-3, EC 201-159-0 MEK ketone2,6-di-tert-Butyl-4- 2,6-Di-tert-butyl-p-cresol, Butylatedhydroxytoluene, BHT methylphenol Butylhydroxytoluene, DBPC, CAS128-37-0, EC 204-881-4 hydroquinone 1,4-dihydroxybenzene,1,4-benzenediol, CAS 123-31-9, EC HQ 204-617-8 Hydroquinone4-methoxyphenol, 4-Hydroxyanisole, 4-MP, HQMME, HQME monomethyl etherMEHQ, MQ-F, CAS 150-76-5, EC 205-769-8 Methylene blue3,7-bis(Dimethylamino)phenazathionium chloride, Basic Blue 9,Tetramethylthionine chloride, CAS 7220-79-3, EC 200- 515-2 Sodiumcarbonate CAS 497-19-8, EC 207-838-8 Na2CO3 Potassium carbonate CAS584-08-7, EC 209-529-3 K2CO3 DESMA Urethane methacrylate, cf. Example 1on page 35 of WO Co1 2009/006282 BA2EO-Ac

  BisPhenol A ethoxylated, diacetate (CAS no. 19224-29-4) Sofl Filler 1Non agglomerated silanized silica nano filler, (50 nm); F1 producedaccording to U.S. Pat. No. 6,899,948 B2 Filler 2 Aggregated Zr/Sinanoclusters; produced as described in U.S. Pat. No. F2 6,730,156,column 25, preparatory example A; surface treated according to processas described in preparatory example B. Filler 3 Ground strontiumcontaining glass filler, <3μm (Schott F3 Glaswerke), surface treatedFiller 4 Fumed silica (Wacker HDKH 2000) F4 BZPBS1-Benzyl-5-phenyl-barbituric acid Ini1 TBPINtert-Butylperoxy-3,5,5-trimethylhexanoate Ini2 Initiator 3Dibutylphenylethylammonium chloride Ini3 Initiator 4 Copper(II)bis(1-phenylpentan-1,3-dione) complex Ini4 CPQ Camphorquinone (CAS no.10373-78-1) Ini5 DPI-PF6 Diphenyliodonium hexafluorophosphate (CAS no.58109-40-3) Ini6 EDMAB Ethyl 4-dimethylaminobenzoate (CAS no.10287-53-3) Ini7 Triphenyl-phosphane Triphenylphosphine, CAS no.603-35-0, EC 210-036-0 PPh3 Triethylamine CAS no. 121-44-8, EC 204-469-4TEAGeneral Procedure A: Synthesis of Diol Precursors (e.g. OR or E2T) ViaEtherification of Dihydroxybenzenes (e.g. Resorcinol) orHydroxyalkylphenols (e.g. Tyrosol) Hydroxybenzoic Acids (e.g. mHB) orvia Nucleophilic Esterification of Hydroxybenzoic Acids (e.g. mHB) withHalogenated Alcohols (e.g. 3-Chloro-1-propanol)

To a solution of the corresponding Dihydroxybenzene orHydroxyalkylphenol and the corresponding Halogenated Alcohol/s in wateran aqueous solution of alkaline hydroxide (e.g. NaOH) or alkalinecarbonate (e.g. Na2CO3) or ammonia is added at reflux. Optionally thesynthesis can be done under a protective gas atmosphere (e.g. nitrogen).

Alternatively IPA or tBuOH can be used as solvent and solid alkalinehydroxide (e.g. KOH) or alkaline carbonate (e.g. Na2CO3) as base.

Also a subsequent reaction pattern is possible for Dihydroxybenzenes orDihydroxybenzene Monoesters (e.g. RAc) where in the first reaction stepone equivalent of base and one half of the Halogenated Alcohol/s isreacted with the Dihydroxybenzene or Dihydroxybenzene Monoester andafterwards in the second reaction step another equivalent of base andthe remaining half of the Halogenated Alcohol/s is reacted (if aDihydroxybenzene Monoester is used then after the first reaction step anester hydrolysis, e.g. a basic ester hydrolysis, has to be done beforethe second reaction step can occur).

After stirring over night at reflux the reaction mixture is cooled toroom temperature, and the reaction mixture is extracted (e.g. MTBE or EAor MEK) if water is used as solvent. Optionally the reaction mixture canbe extracted as it is or the organic phase can be separated and only theaqueous phase can be extracted, afterwards the organic phase is combinedwith the extracts. Optionally the combined organic phases can beextracted with aqueous alkaline (e.g. NaOH) solutions and/or aqueousacid (e.g. H2SO4) solutions and/or water.

If IPA or tBuOH is used as solvent the reaction mixture is firstfiltered to remove the precipitate, then the solvent is stripped off invacuo, and then the residue is extracted against water as describedabove.

If a Hydroxybenzoic Acid is used as building block first the reactionmixture is acidified with aqueous acid (e.g H2SO4) and then extractedagainst water as described above to isolate the etherification productHydroxyalkoxybenzoic Acid and/or the nucleophilic esterification productHydroxybenzoic Acid Hydroxyalkyl Ester.

Optionally the combined organic phases are filtered through silica oralumina and/or are stirred with charcoal to achieve improveddecolorization. After drying over anhydrous Na2SO4 and filtration thesolvent is stripped off in vacuo.

Alternatively an alkylation according to the so-called Carbonate Methodaccording to Houben-Weyl, Methoden der Organischen Chemie, Band VI/3Teil 3, Sauerstoffverbindungen 1, 4. Auflage, 1965, Georg Thieme Verlag,Stuttgart, p. 55, or a deacylating alkylation of mono or diacylatedDihydroxybenzenes (e.g. RAc or RAc2) according to Houben-Weyl, Methodender Organischen Chemie, Band VI/3 Teil 3, Sauerstoffverbindungen 1, 4.Auflage, 1965, Georg Thieme Verlag, Stuttgart, p. 59, is possible.

General Procedure B: Synthesis of Diol Precursors (e.g. OER) ViaEtherification of Already Alkoxylated Dihydroxybenzenes (e.g.ethoxylated resorcinol) with Halogenated Alcohols (e.g.3-Chloro-1-propanol)

Under a protective gas atmosphere (e.g. nitrogen) to a mixture of thecorresponding Already Alkoxylated Dihydroxybenzene and the correspondingHalogenated Alcohol/s a solution of KOtBu in e.g. THF or tBuOH is addedslowly at elevated temperature (e.g. 80° C.). After stirring over nightat elevated temperature the reaction mixture is cooled to roomtemperature, the precipitate is separated by filtration, and the solventis stripped off from the filtrate in vacuo. Optionally furtherpurification of this residue via an aqueous workup as described inGeneral Procedure A can be achieved.

General Procedure C: Synthesis of Ethoxylated Diol Precursors (e.g. ET)Via Etherification of Hydroxyalkylphenols (e.g. Tyrosol) with EthyleneCarbonate

To a solution of the corresponding Hydroxyalkylphenol and EthyleneCarbonate in IPA or tBuOH solide alkaline hydroxide (e.g. KOH) oralkaline carbonate (e.g. K2CO3) or alkaline tert-butoxide (e.g. KOtBu)is added and the reaction mixture is stirred at reflux over night.Optionally the synthesis can be done under a protective gas atmosphere(e.g. nitrogen).

The reaction mixture is cooled to room temperature, the solvent isstripped off in vacuo, and then the residue is extracted against waterand further worked up as described in General Procedure A. Optionallythe isolated product can be further purified by crystallization usingwater as solvent.

General Procedure D: Synthesis of Diol Precursors (e.g. PGT) ViaAddition of Dihydroxybenzenes (e.g. 4-tert-Butylcatechol) orHydroxyalkylphenols (e.g. Tyrosol) or Hydroxybenzoic Acids (e.g. mHB) orAlready Etherified and/or Nucleophilic Esterified Hydroxybenzoic Acids(e.g. OmHB) onto Epoxies (e.g. GP or GMA) under Ring-Opening

-   Solvent Base Route: To an aqueous solution of the corresponding    Hydroxyalkylphenol (e.g. Tyrosol) and alkaline hydroxide (e.g. NaOH)    or alkaline carbonate (e.g. Na2CO3) or ammonia the epoxy (e.g. GP)    is added at reflux. Optionally the synthesis can be done under a    protective gas atmosphere (e.g. nitrogen). Optionally the synthesis    can be done using IPA or HOtBu as solvent and solid alkaline    hydroxide (e.g. KOH) or alkaline carbonate (e.g. K2CO3) or alkaline    tert-butoxide (e.g. KOtBu). After stirring over night at reflux the    reaction mixture is cooled to room temperature, and the reaction    mixture is extracted and further worked up as described in General    Procedure A.-   Solvent Free Route: To the mixture of the corresponding    Dihydroxybenzenes (e.g. 4-tert-Butylcatechol) and the epoxy (e.g.    GMA) a catalyst (e.g. PPh₃ or TEA) is added under stirring and the    reaction mixture is warmed to an elevated temperature. Optionally    the synthesis can be done under a protective gas atmosphere (e.g.    nitrogen). After stirring over night at elevated temperature the    reaction mixture is cooled to room temperature, and the reaction    mixture is extracted and further worked up as described in General    Procedure A.    Optionally the isolated product can be further purified by    crystallization using water as solvent or by fractionated subsequent    organic-organic extraction using organic solvents of different    polarities.    General Procedure E: Acid Catalyzed (e.g. MSA) Esterification of    Diol Precursors (e.g. OR) with Unsaturated Acids (e.g. MA)

To the corresponding Diol Precursor in e.g. cyclohexane or ahexane/toluene mixture or a cyclohexane/toluene mixture BHT, HQME,optionally methylene blue and/or HQ, the catalyst (e.g. MSA) and theunsaturated acid (e.g. MA) are added. At reflux water is removed using aDean Starck apparatus. After completion of the reaction the crudereaction mixture is extracted at least twice with 4N NaOH solution or 2NNaOH solution, then at least once washed with water, and then dried overanhydrous Na2SO4. After filtration, the filtrate is optionally filteredthrough basic alumina. 100-300 ppm of BHT and 100-300 ppm of HQME areadded to the filtrate. Then the solvent is stripped off in vacuo whileair is bubbling through the crude sample.

EBP-MA Comparative Example 1

-   commercially available monomer.

OBP-MA Comparative Example 2

-   Synthesis according to DE 19 21 869, Example 11.-   ER-MA (Comparative Example 3    According to General Procedure E 118.6 g of ER, 13.0 g of MSA, and    150.3 g of MA were reacted to give 148.2 g of ER-MA as a yellowish    oil that crystallizes at room temperature readily to a colorless    solid (m.p.>60° C.).

EH-MA Comparative Example 4

According to General Procedure E 118.6 g of EH, 13.0 g of MSA, and 150.3g of MA were reacted to give 118.3 g of EH-MA as a colorless solid(m.p.>80° C.) immediately after synthesis.

E4R-MA Comparative Example 5

According to General Procedure A 51.0 g of resorcinol, 47.7 g of NaOH,and 138.5 g of 2-(2-chloroethoxy)-ethanol were reacted in 200 mL ofwater to give 104.1 g of E4R. According to General Procedure E 190.0 gof E4R, 12.3 g of MSA, and 171.4 g of MA were reacted to give 238.9 g ofE4R-MA.

OR-MA Comparative Example 6

According to General Procedure A 51.0 g of resorcinol, 48.2 g of NaOH,and 105.1 g of 3-chloro-1-propanol were reacted in 200 mL of water togive 102.7 g of OR.

According to General Procedure E 180.0 g of OR, 13.1 g of MSA, and 205.5g of MA were reacted to give 288.3 g of OR-MA as a yellowish oil thatcrystallizes at room temperature readily to a colorless solid (m.p.>30°C).

EER-MA Inventive Example 1

According to the subsequent reaction pattern of General Procedure Afirst 50.0 g of resorcinol, 27.5 g of NaOH, and 55.4 g of2-chloro-1-ethanol were reacted over night at a reaction temperature of40° C. in 155 mL of water, then 75.0 g of 2-(2-chloroethoxy)-ethanol and27.5 g of NaOH dissolved in 44.4 mL of water were added under reflux andthe reaction mixture was kept at reflux over night to give 78.2 g ofEER. According to General Procedure E 74.0 g of EER, 5.20 g of MSA, and78.9 g of MA were reacted to give 105.5 g of EER-MA.

OER-MA Inventive Example 2

According to General Procedure B 60.0 g of ethoxylated resorcinol (ER),31.5 g of 3-chloro-1-propanol, and 165.4 g of a 1.7M KOtBu solution inTHF were reacted to give 63.5 g of OER. According to General Procedure E85.0 g of OER, 5.80 g of MSA, and 85.7 g of MA were reacted to give117.6 g of OER-MA.

OOR-MA Inventive Example 3

According to General Procedure B 20.0 g of OR, 8.53 g of3-chloro-1-propanol, and 88.4 mL of a 1M KOtBu solution in HOtBu werereacted to give 20.3 g of OOR. According to General Procedure E 17.0 gof OOR, 1.10 g of MSA, and 15.4 g of MA were reacted to give 23.2 g ofOOR-MA.

OE2R-MA Inventive Example 4

According to General Procedure A 51.0 g of resorcinol, 47.7 g of NaOH,69.2 g of 2-(2-chloroethoxy)-ethanol, and 51.5 g of 3-chloro-1-propanolwere reacted in 200 mL of water to give 93.5 g of OE2R. According toGeneral Procedure E 55.0 g of OE2R, 3.80 g of MSA, and 55.4 g of MA werereacted to give 71.4 g of OE2R-MA.

HOR-MA Inventive Example 5

According to General Procedure A 51.0 g of resorcinol, 47.7 g of NaOH,75.9 g of 6-chlorohexanol, and 51.5 g of 3-chloro-1-propanol werereacted in 200 mL of water to give 115.2 g of HOR. According to GeneralProcedure E 70.0 g of HOR, 4.67 g of MSA, and 67.4 g of MA were reactedto give 101.7 g of HOR-MA.

HOR-A Inventive Example 6

According to General Procedure E 43.7 g of HOR, 2.68 g of MSA, and 35.2g of acrylic acid (AA) were reacted to give 54.8 g of HOR-A.

POR-MA Inventive Example 7

According to General Procedure A 51.0 g of resorcinol, 47.7 g of NaOH,68.2 g of 5-chloropentanol, and 51.5 g of 3-chloro-1-propanol werereacted in 200 mL of water to give 85.2 g of POR. According to GeneralProcedure E 81.9 g of POR, 5.60 g of MSA, and 83.2 g of MA were reactedto give 119.8 g of POR-MA.

OE2C-MA Inventive Example 8

According to General Procedure A 50.0 g of catechol, 49.0 g of NaOH,75.0 g of 2-(2-chloroethoxy)-ethanol, and 51.5 g of 3-chloro-1-propanolwere reacted in 200 mL of water to give 67.7 g of OE2C. According toGeneral Procedure E 65.0 g of OE2C, 4.40 g of MSA, and 65.5 g of MA werereacted to give 88.3 g of OE2C-MA.

E4RE-MA Inventive Example 9

According to General Procedure A 48.8 g of 1,3-dihydroxy-4-ethylbenzene,64.0 of KOH, and 113.2 g of 2-(2-chloroethoxy)-ethanol were reacted in280 mL of water to give 58.7 g of E4RE. According to General Procedure E57.6 g of E4RE, 3.57 g of MSA, and 47.3 g of MA were reacted to give71.4 g of E4RE-MA.

E4RH-MA Inventive Example 10

According to General Procedure A 68.6 g of 1,3-dihydroxy-4-hexylbenzene,39.2 of NaOH, and 113.2 g of 2-(2-chloroethoxy)-ethanol were reacted in275 mL of water to give 110.0 g of E4RH. According to General ProcedureE 107.0 g of E4RH, 6.20 g of MSA, and 74.6 g of MA were reacted to give108.2 g of E4RH-MA.

ORE-MA Inventive Example 11

According to General Procedure A 49.6 g of 4-ethylresorcinol, 37.7 g ofNaOH, and 81.4 g of 3-chloro-1-propanol were reacted in 200 mL of waterto give 76.2 g of ORE. According to General Procedure E 72.4 g of ORE,5.00 g of MSA, and 73.5 g of MA were reacted to give 107.4 g of ORE-MA.

ORH-MA Inventive Example 12

According to General Procedure A 32.9 g of 4-hexylresorcinol, 17.8 g ofNaOH, and 37.7 g of 3-chloro-1-propanol were reacted in 130 mL of waterto give 39.8 g of ORH. According to General Procedure E 39.8 g of ORH,1.13 g of MSA, and 33.1 g of MA were reacted to give 54.8 g of ORH-MA.

EBC-MA Inventive Example 13

According to General Procedure C 30.0 g of 4-tert-butylcatechol, 3.54 gof KOH, and 47.7 g of ethylene carbonate were reacted in 40 g of IPA togive 46.5 g of EBC. According to General Procedure E 46.0 g of EBC, 2.89g of MSA, and 38.9 g of MA were reacted to give 65.8 g of EBC-MA.

EEBC-MA Inventive Example 14

According to the subsequent reaction pattern of General Procedure Afirst 37.4 g of 4-tert-butylcatechol, 13.5 g of NaOH, and 27.1 g of2-chloro-1-ethanol were reacted over night at a reaction temperature of40° C. in 128 mL of water, then 36.4 g of 2-(2-chloroethoxy)-ethanol and13.5 g of NaOH dissolved in 22 mL of water were added under reflux andthe reaction mixture was kept at reflux over night to give 59.4 g ofEEBC. According to General Procedure E 59.4 g of EEBC, 3.77 g of MSA,and 51.4 g of MA were reacted to give 71.8 g of EEBC-MA.

E4BC-MA Inventive Example 15

According to General Procedure A 76.2 g of 4-tert-butylcatechol, 47.7 ofNaOH, and 138.5 g of 2-(2-chloroethoxy)-ethanol were reacted in 300 mLof water to give 124.9 g of E4BC. According to General Procedure E 58.7g of E4BC, 3.50 g of MSA, and 44.3 g of MA were reacted to give 45.7 gof E4BC-MA.

OBC-MA Inventive Example 16

According to General Procedure A 77.0 g of 4-tertbutylcatechol, 48.2 ofNaOH, and 105.1 g of 3-chloro-1-propanol were reacted in 300 mL of waterto give 119.1 g of OBC. According to General Procedure E 60.0 g of OBC,3.91 g of MSA, and 54.9 g of MA were reacted to give 81.0 g of OBC-MA.

OE2BC-MA Inventive Example 17

According to General Procedure A 69.6 g of 4-tertbutylcatechol, 45.3 gof NaOH, 67.8 g of 2-(2-chloroethoxy)-ethanol, and 47.1 g of3-chloro-1-propanol were reacted in 275 mL of water to give 113.2 g ofOE2BC. According to General Procedure E 56.7 g of OE2BC, 3.50 g of MSA,and 46.9 g of MA were reacted to give 67.3 g of OE2BC-MA.

BC-GMA Inventive Example 18

According to General Procedure D (Solvent Free Route) 50.0 g of4-tert-butylcatechol, 0.68 g of TEA, and 85.5 g of GMA were reacted at atemperature of 80° C. to give 114.6 g of BC-GMA.

PGT-AM Inventive Example 19

According to General Procedure D (Solvent Based Route) 100.0 g oftyrosol, 5.73 g of NaOH, and 108.0 g of GP were reacted in 200 mL ofwater to give 203.4 g of crude PGT. After re-crystallization from water188.9 g of purified PGT were collected. According to General Procedure E218.5 g of purified PGT and 12.5 g of MSA were first reacted with 68.5 gof MA and then reacted with 82.0 g of AA to give 295.2 g of PGT-AM.

ET-MA Inventive Example 20

According to General Procedure C 100.0 g of tyrosol, 7.02 g of KOH, and82.0 g of ethylene carbonate were reacted in 100 g of IPA to give 112.5g of crude ET. After re-crystallization from water 74.5 g of purified ETwere collected. According to General Procedure E 20.0 g of purified ET,1.48 g of MSA, and 23.6 g of MA were reacted to give 33.2 g of ET-MA.

E2T-MA Inventive Example 21

According to General Procedure A 50.0 g of tyrosol, 44.9 og NaOH, and136.6 g of 2-(2-chloroethoxy)-ethanol were reacted in 200 mL of water togive 88.1 g of E2T. According to General Procedure E 60.0 g of E2T, 2.80g of MSA, and 22.8 g of MA were reacted to give 85.2 g of E2T-MA.

OT-MA Inventive Example 22

According to General Procedure A 40.0 g of tyrosol, 19.7 og KOH, and34.9 g of 3-chloro-1-propanol were reacted in 40 g of IPA to give 49.7 gof OT. According to General Procedure E 49.70 g of OT, 3.54 g of MSA,and 54.4 g of MA were reacted to give 79.7 g of OT-MA.

MGT-MA Inventive Example 23

According to General Procedure D (Solvent Based Route) 51.0 g oftyrosol, 10.9 mL of a 1M KOtBu solution in HOtBu, and 46.8 g of GMA werereacted to give 37.2 g of crude MGT. After fractionated subsequentorganic-organic extraction using toluene/hexane mixtures as well as purecyclohexane and pure hexane to remove unwanted very unpolar as well asunwanted very polar by-products 9.50 g of purified MGT-MA werecollected.

Synthesis of Light Curing One Component Compositions

Some of the compounds synthesized were used for producing a (dental)composition.

The compositions produced and tested with respect to their mechanicalproperties are given in Table 2 below. In Table 2 the values of thecomponents represent %-weight of the individual components in thecorresponding dental formulation.

General Procedure I:

With magnetic stirring and under the exclusion of light the initiatorsystem components were dissolved within the monomers at temperatures notabove 50° C. (depending on the intrinsic viscosity of the usedmonomers).

General Procedure II:

According to General Procedure I the initiator system components weredissolved within the monomers. Under the exclusion of light and using atwo-arm kneader the filler was mixed in portions with this mixture ofinitiator system and monomers. The amount of filler was manuallydetermined depending on the desired handling properties of the dentalcomposition. The dental composition was then light cured using a 800 mWhalogen curing light (3M ESPE Elipar™ Trilight) and tested according tothe corresponding measurements listed above. The respective values aregiven in Table 2.

Dental Compositions A and B contain either of components CE1 or CE2 butnot compound (A) according to the invention. In Table 2 below, compound(A) is represented by components IE1, IE4, and IE20. Thus, DentalCompositions A and B can be considered as Comparative Examples, whereasDental Compositions C to E can be considered as Inventive Examples.

TABLE 2 Dental Composition A B C D E CE1 22.2 CE2 22.2 IE1 22.2 IE4 22.2IE20 22.2 Ini5 0.03 0.03 0.03 0.03 0.03 Ini6 0.19 0.19 0.19 0.19 0.19Ini7 0.09 0.09 0.09 0.09 0.09 F1 7.36 7.36 7.36 7.36 7.36 F2 70.1 70.170.1 70.1 70.1 CS 1 420 ± 387 ± 35.0 461 ± 22.0 469 ± 21.0 445 ± 22.0[MPa] 21.0

As can be seen, compositions containing compound (A) according to theinvention are superior with respect to compressive strength (CS 1)compared to compositions not containing compound (A) according to theinvention.

Synthesis of Chemical Curing Two Component Compositions

Some of the compounds synthesized were used for producing a (dental)composition.

The compositions produced and tested with respect to their mechanicalproperties are given in Tables 3, 4, 5 and 6.

In Tables 3 and 4 the values of the components represent %-weight of theindividual components in the corresponding dental formulation. In Tables5 and 6 the values of the components Base 1 to CAT represent relative %of the individual components in the corresponding dental formulation.

General Procedure III:

Under the exclusion of light the components listed in Tables 3 and 4were mixed in a three-arm laboratory kneader. Residual agglomerates werehomogenized in a ceramic three-roller mill.

General Procedure IV:

The pastes listed in Tables 3 and 4 that were made according to GeneralProcedure III were filled into the respective compartments of a 10:1SulzerMixpac™ cartridge. The material was then applied into therespective metal moulds using a Garant™ II 10:1 cartridge equipped witha static mixer (SulzerMixpac Company). Cure was effected under pressurebetween plastic foil (Hostaphan™ RN75) and plexiglass plates for 1 h at23° C. Then the press, plexiglass plates, and foil were removed, and thespecimens within the moulds were subjected to post-cure at 36° C. underdemineralized water for 23 h. The moulds were removed immediately beforemeasurement. The cured specimens were tested according to thecorresponding measurements listed above. The respective values are givenin Tables 5 and 6.

-   -   Dental Composition—Bases 1, 2, and 3 contain either of        components CE1, CE2 or CE5 but not compound (A) according to the        present invention. In Tables 3 and 4 below, compound (A) is        represented by components IE1, 1E2, 1E4, 1E16, 1E19 and 1E20.        Thus, Dental Composition—Bases 1, 2, and 3 can be considered as        belonging to a Comparative Example, whereas Dental        Compositions—Bases 4 to 9 can be considered as belonging to        Inventive Examples.

TABLE 3 Dental Composition Base 1 Base 2 Base 3 Base 4 Base 5 Base 6 Co113.1 13.1 13.1 13.1 13.1 13.1 CE1 52.4 CE2 52.4 CE5 52.4 IE1 52.4 IE252.4 IE4 52.4 IE16 IE19 IE20 Ini3 0.15 0.15 0.15 0.15 0.15 0.15 Ini4<0.01 <0.01 <0.01 <0.01 <0.01 <0.01 F3 26.3 26.3 26.3 26.3 26.3 26.3 F48.00 8.00 8.00 8.00 8.00 8.00 Sof1 F4 Ini1 Ini2

TABLE 4 Dental Composition Base 7 Base 8 Base 9 CAT Co1 13.1 13.1 13.1CE1 CE2 CE5 IE1 IE2 IE4 IE16 52.4 IE19 52.4 IE20 52.4 Ini3 0.15 0.150.15 Ini4 <0.01 <0.01 <0.01 F3 26.3 26.3 26.3 F4 8.00 8.00 8.00 Sof179.7 F4 10.0 Ini1 10.0 Ini2 0.30

Dental Compositions F, G, and H contain Bases 1, 2, or 3 and CAT,compositions which both contain components according to the state of theart. Dental Compositions I to M contain a Base component containing acompound (A) according to the present invention and a CAT componentcontaining components according to the state of the art. Thus, DentalCompositions I to M can be considered as Inventive Examples.

TABLE 5 Dental Composition F G H I J K Base 1 90.9 Base 2 90.9 Base 390.9 Base 4 90.9 Base 5 90.9 Base 6 90.9 Base 7 Base 8 Base 9 CAT 9.19.1 9.1 9.1 9.1 9.1 CS 2 260.0 ± 251.2 ± 235.4 ± 370.5 ± 300.7 ± 325.1 ±[MPa] 19.0 13.5 38.0 25.7 34.3 19.1

TABLE 6 Dental Composition K L M Base 1 Base 2 Base 3 Base 4 Base 5 Base6 Base 7 90.9 Base 8 90.9 Base 9 90.9 CAT 9.1 9.1 9.1 CS 2 296.0 ± 18.6292.3 ± 14.7 285.1 ± 17.2 [MPa]

As can be seen, compositions containing compound (A) according to theinvention are superior especially with respect to compressive strength(CS 2) compared to compositions not containing compound (A) according tothe invention.

1. A dental composition comprising: Polymerizable monomer (1), Initiatorcomponent(s), Filler component(s) in an amount of more than about 20wt.-%, wt.-% with respect to the whole weight of the composition, thepolymerizable monomer (1) being characterized by formula (I)

with: B—O-A-[-O—B′—]_(a) representing the unsymmetrical monomer backboneas linkage between the reactive (meth)acrylate moieties, a=0 or 1, Abeing selected from:

A being always attached as aryl-alkyl ether onto B and/or B′, B beingselected from: *—(CH₂)_(b)—* , *—(CH₂—CH₂—O—CH₂—CH₂)—*,*—(CH₂—CH₂—O—CH₂—CH₂—CH₂)—*, *—(CH₂—CH₂—CH₂—O—CH₂—CH₂—CH₂)—*,

B being always attached as alkyl ester onto the (meth)acrylate reactivemoiety, b=2 to 6, B′ being selected from *—(CH₂)_(b)—*,*—(CH₂—CH₂—O—CH₂—CH₂)—*,

B′ being always attached as alkyl ester onto the (meth)acrylate reactivemoiety, b′=2 to 6, R═H, methyl, X being selected from H, methyl, ethyl,hexyl, tert-butyl, “*” representing those site(s) of a moiety of themonomer, where that moiety is bonded to another moiety of the monomer.2. The dental composition according to claim 1, the polymerizablemonomer (1) being characterized by either formula (Ia) or formula (Ib)

with: B—O-A-O—B′ being an unsymmetrical monomer backbone as linkagebetween the reactive (meth)acrylate moieties, A being selected from

A being always attached as aryl-alkyl ether onto B and B′, B beingselected from: *—(CH₂)_(b)—*, *—(CH₂—CH₂—O—CH₂—CH₂)—*,*—(CH₂—CH₂—O—CH₂—CH₂—CH₂)—*, *—(CH₂—CH₂—CH₂—O—CH₂—CH₂—CH₂)—*,

B being always attached as alkyl ester onto the (meth)acrylate reactivemoiety, b=2 to 6, B′ being selected from: *—(CH₂)_(b)—*,*—(CH₂—CH₂—O—CH₂—CH₂)—*,

B′ being always attached as alkyl ester onto the (meth)acrylate reactivemoiety, b′=2 to 6, R═H, methyl, X═H, methyl, ethyl, hexyl, tert-butyl;or

with: B—O-A being an unsymmetrical monomer backbone as linkage betweenthe reactive (meth)acrylate moieties, A being selected from:

A being always attached as aryl-alkyl ether onto B and always attachedas alkyl ester onto the (meth)acrylate reactive moiety, B being selectedfrom: *—(CH₂)_(b)—*, *—(CH₂—CH₂—O—CH₂—CH₂)—*,

B being always attached as alkyl ester onto the (meth)acrylate reactivemoiety, b=2 to 6, R═H, methyl; “*” representing those sites of a moietyof the monomer, where that moiety is bonded to another moiety of themonomer.
 3. The dental composition according to claim 1 beingcharacterized by at least one or all of the following features: thepolymerizable monomer (1) having a molecular weight of about 300 toabout 600, the polymerizable monomer (1) not solidifying at 23° C. 4.The dental composition according to claim 1, the polymerizable monomer(1) being selected from one of the following monomers and mixturesthereof:


5. The dental composition according to claim 1, the polymerizablemonomer (1) being selected from one of the following monomers andmixtures thereof:

R being always independently selected from H and CH3.
 6. The dentalcomposition according to claim 1, the initiator being selected fromradiation curing, redox curing, heat curing initiators and combinationsthereof.
 7. The dental composition according to claim 1 comprising therespective components in the following amounts: Polymerizable monomer(s)(1): from about 1 to about 75 wt.-%, Initiator(s): from about 0.1 toabout 10 wt.-%, Filler(s): from about 20 to about 90 wt.-%,
 8. Thedental composition according to claim 1 comprising in addition apolymerizable monomer (2) comprising a urethane moiety,
 9. The dentalcomposition according to claim 1 not comprising solvent(s) in an amountabove about 10 wt.-%.
 10. The dental composition according to claim 1,the adhesive composition being characterized by at least one or all ofthe following features before curing: Viscosity: from about 0.5 to about200 Pa*s measured at 23° C. with a shear rate of 100 l/s; pH value ifbrought in contact with water: about 1 to about 9, radiation or redoxcuring, storage stable.
 11. The dental composition according to claim 1,the adhesive composition being characterized by the following featureafter curing: Compressive strength determined according to ISO 4049using specimens having the dimension of 3 mm×3 mm×5 mm: at least about430 MPa. Compressive strength of the dental formulation determinedaccording to DIN 53454 using cylindrical specimens with a diameter of 4mm and a height of 8 mm: at least about 280 MPa.
 12. The dentalcomposition according to claim 1 being characterized as follows:Polymerizable monomer(s) (1) being represented by the formula asdescribed in any of claims 2 to 5 in an amount from about 1 to about 75wt.-%, Initiator(s), being selected from radiation curing or redoxcuring initiator(s), Filler(s) being selected from silica orsilica/zirconia filler(s) and mixtures thereof, in an amount from about20 to about 90 wt.-%.
 13. The dental composition according to claim 1being provided as one or two part system.
 14. Use of the dentalcomposition as described in claim 1 as or for producing a dental fillingmaterial, crown and bridge material, inlay, onlay, veneer or dental millblank.
 15. Use of the dental composition as described in claim 1 forproducing a dental restoration like a dental crown, bridge, onlay orinlay by applying a rapid-prototyping technique.